Ok, man here you go. I added in 17 of the cards you purchased and for the record, many of them are very good. So, good job lol. With those cards in, I also added three more cards you'll need to pick up but there's a catch, which I'll explain down below.

The Swaps

Change 1

Out:  In: 

This change is pretty straightforward. Our deck cares about creatures with flying. Simply put, Anger Turtle doesn't help the deck in any way. Dragonlord Ojutai on the other hand does a lot. First, it does have flying so it interacts with almost everything in the deck. The Hexproof is still present (at least half the time) and it offers some great card advantage... All for two fewer mana.

Change 2

Out:  In:

Archon of Redemption isn't a bad card but it's not a great card either - At least not for this deck. There are no lifegain synergies in the deck and the effect is pretty conditional and underwhelming. Say you're in the late game and doing well; This isn't likely to do very much for you and definitely won't close out games. If you're behind and looking to catch up, this probably won't dig you out of a hole.

Donal, Herald of Wings on the other hand stands to do a lot more. There are tons of great effects in the deck that would be awesome to copy up on. For example, Cloudblazer, Jubilant Skybonder, and Skycat Sovereign would all be awesome copies to have of even as 1/1's.

Change 3

Out:  In:

Again, the reason Aven Gagglemaster gains life and doesn't do much of anything else. In fact, if you play it onto an empty bored you'll only gain two life... Not great for five mana. Battle Angels of Tyr costs less mana, has better power/toughness, can draw cards, make treasures, and gain life.

Change 4

Out:  In:

There's not a direct comparison to be made here as they do vastly different things. This one boils down to Cartographer's Hawk being slow. It's not bad (and ramp is great but you have enough without this) but having to recast it over and over isn't awesome. Magus of the Moat is an amazing payoff for playing so many creatures with flying and can greatly affect games. 

Change 5

Out: ((Faerie Formation}} In:

The best part of Faerie Formation is that it draws a card when you activate its ability. You of course also get the token and the 5/4 flying creature as well. The only real downside is that it costs a total of nine mana (five for the card and then four more per activation) which isn't ideal.

Watcher of the Spheres is cheap to cast, which helps a lot. When a card has an effect like this you don't want it to cost five or six mana... At two mana there will be lots of creatures to follow to trigger this. However, I think both cards are good - They're just different. That said, you've got plenty of creatures with flying and ways to draw cards without Faerie Formation. And you paid money for Watcher of the Spheres so I added it. If you don't want to make this swap you don't have to.

Change 6

Out:  In: 

You may be catching onto some trends at this point. Diluvian Primordial costs a lot of mana and the only thing it truly contributes to the gameplan is that it has flying. There is the stealing of instants and sorceries but that's not really relevant to what you want to be doing.

Medomai the Ageless on the other hand is. Who doesn't love taking an extra turn? Sometimes this will just happen naturally and that's wonderful. However, I included another card to abuse the ability. Now, before I get into this I want to lead with This Is An Infinite Combo! and not all playgroups are down with that. If you're not wanting a combo in the deck simply leave this second piece out. If you're ok with it, ask your friends if they are, and if all is well here's what you'll do:

When I saw you bought Medomai the Ageless I also added Phantom Steed. Here's how the combo works.

You need to have Medomai the Ageless exiled with the first ability of Phantom Steed. Now, whenever you attack with Phantom Steed you'll create a token of Medomai the Ageless that's tapped and attacking. Considering it entered already attacking you get around the "cannot attack on an extra turn" clause. Assuming an opponent can't block her, she'll deal damage and you'll get an extra turn.

You then simply repeat this process over and over again and the result is infinite turns. Again, if you don't want to overpower your playmates simply leave Phantom Steed and add back in Steel-Plume Marshal.

Change 7

Out: In:

Kangee's Lieutenant is good but Kira, Great Glass-Spinner is better. We've got the flying/attacking bases pretty well covered at this point and it's easy to only focus on the offensive game plan and not protect your things. Kira, Great Glass-Spinner makes it so that opponents will need two removal spells to remove your stuff instead of one. Cards like this are the unsung heroes that make sure every other card I've mentioned can do its thing.

Change 8

Out: In:

Austere Command is a great card and I'm glad you bought it. You know good cards when you see them! The reason it's good is its versatility. Do you have a board full of artifacts and tokens? Choose the options you need. One giant creature and a few enchantments? Well, wipe the board accordingly. Time Wipe isn't bad but it's not nearly as good.

Change 9

Out: In:

I replace Crush Contraband in every precon I buy. It's really just a bit too narrow and a bit too much mana. I counted the number of removal spells you have and you'll do fine without this. So, I cut it to make room for Reconnaissance Mission, which is a great card by the way.

Change 10

Out: In:

Vow of Duty does almost nothing for the deck. This is one of the cards that seem to be added in a lot of precons to get up to 100 cards. I promise you won't miss it. Doubling Cube is an interesting card but it's not always good without some support. Here's where the other two cards you'll need to pick up come in. But again, this is pretty powerful so feel free to leave it out.

As mentioned, the cube all alone probably won't generate much more than one or two mana most of the time. Where the card excels is when you can fill your mana pool in one big burst and then double it. So, I included a copy of High Tide. You can cast it, tap a bunch of islands, and get double mana for each one. Then spend three, activate the cube, and double up. This makes the card more effective.

Taking things a step further, I added a copy of Dramatic Reversal as well, which will allow you to untap your stuff (including Doubling Cube) and use it again. So, you'll be quadrupling your mana when this works out. Of course, this can just untap all your creatures as well! If you don't want this included let me know and I will tweak things some. It's no trouble, just let me know.

To make room for High Tide and Dramatic Reversal I removed Rally of Wings and Sharding Sphinx. Sharding Sphinx isn't great because there are only two artifact creatures in the deck.

Change 11

Out: In:

Gideon Jura doesn't really contribute to the strategy in any meaningful way. He can remove a creature with his -2 but aside from that there isn't much going on. And while this isn't the ideal build for Narset (because there are so many creatures in the deck) she still goes a long way in shutting down opposing decks.

Change 12

Out: In:

Soul Snare is pretty narrow. It only removes attacking creatures and even then, only if they're attacking you. Resculpt can hit any creature or artifact, so it'll be more useful, more often.

Change 13

Out:  In: 

Inspired Sphinx is pretty good at it's best (you draw three cards) and pretty bad at it's worst (you draw one card) and it costs a lot of mana no matter the circumstances. So, we can afford to cut it. Because Dream Trawler is an all-star. Flying, lifelink, card draw, pumps itself up and has some built-in protection all for six mana? Yes to all of that and this is absolutely a wincon for your deck.

Change 14

Out: In:

Honestly, I think Hedron Archive is a fine card. It's ramp when you need ramp and card draw when you don't. Mind Stone is the exact same thing except it costs less mana and gives you less mana. There's small upsides to both cards and I just swapped this so you could play more cards that you ordered and the deck would be a tad faster. That said, you could leave Hedron in and be a-ok... Just whichever you prefer.

Change 15

• Out:
  • Plains
  • Island
  • Meandering River
• In:
  • Ghost Quarter
  • Reliquary Tower
  • Skycloud Expanse

We simply went land for land here - Meandering River does nothing but give you blue and white mana and enters tapped. Skycloud Expanse does the exact same thing (even better actually) and doesn't slow you down by coming in tapped. Then, I simply removed one of each basic land for the Reliquary Tower and Ghost Quarter.

The deck can go down two basic without issue just be sure to remember that they don't produce colored mana if you get them in your opening hand. And finally, you may not even need Ghost Quarter unless you're having trouble out of specific opposing lands... Just test it out and see if you find it helpful.

Conclusion

You bought very good cards for your precon. The deck will be more solid with these changes for sure. With the combo and the Doubling Stone + High Tide + Dramatic Reversal it will be pretty powerful too. But again, it's perfectly normal to want to leave them out to keep everything nice and even. On the other hand, I could also help your friends to upgrade their decks some.:)

Post upgrades the deck is very well rounded. Your numbers for ramp, card draw (you're excelling here), removal, board wipes, and land is all solid and your mana curve is great too. Enjoy.