This is me replying as an EggWars player, not QA;
Realistically, adding back leather armour will not change much early game for anyone here. I doubt anyone here is going to die because of it, the only change you'll see is that anyone not as good will die quicker because it has a lot less protection, and you win faster in public games. (You will also see the change I will talk about later, indirectly, but that's not in your reasons).
Because everyone here keeps screaming I don't play Bedrock (the client sucks leave me alone) to anything I say, I've played a bunch of Mega, and fours games over the last few days and I'm fairly convinced the same would happen on Bedrock. If you think otherwise, feel free to convince me otherwise, I know I don't play Bedrock as often as any of you so I will listen. (I know playing it for a few days isn't the same, but it's better than once a few month for non-qa reasons. And, the client is such a pain I can't play it more than this sorry 🙏)
On a related note, please start using leaps, you all die way too easy, once in the void and you're dead. But mad respect with that painfully slow shop, you have my condolences 
I'm also convinced all of you have the current problem backwards, there is no need for less durability in the early game. There is need for less durability in the late game. The reason no one is dying now is because diamond armour is dirt cheap, and breaks so slow that you are fine just having one extra set and replacing everything at once, rather than sometimes losing two pieces and dying due to dmg because you replaced it to slow. Which is rather boring to say the least.
I do think armour should be shifted a slot, such that diamond armour costs diamonds, this way the much higher durability ones will not be this cheap, and people will actually run out of it when fighting. As you have some control over it, it's easy to limit someone's diamond intake. You can't do this for gold really.
So, adding in chain armour, as proposed above, as the first seems more reasonable than leather to me. It would also be a lot less of a drastic change, since chain is a lot closer to iron in term of protection. Yes I know, chain & iron have the same dura, but again, I don't think a change is needed early game. I only think we need less easy access to dura in the late game.
I also don't want prot 4 to return, on Java we played it with half health, having to half your health to make the game playable means it wasn't balanced 
As for prices, I don't want it how it was before, nor do I want all pieces to cost the same (as some people have suggested). A chest plate is much better than a helmet, it should cost more !!.
I think just changing gold to diamond for diamond armour is fine. I want it to be rather cheap, but always more than 16 (amount on a lvl3 dia gen).
Iron to gold, can also be the same ig. And the chain could be 4 iron ig to make some people that are obsessed with the old prices happy. Anyway, I've not got too much of an opinion on the prices. They're rather trivial to me really.
I do like what was said above about it being always available which should help people just respawning. I've never not have enough for 4 iron armour, but I've needed to run back for 10 iron armour 
On a final note, anyone that wants nether armour gone just has a skill issue and anyone with less than 75 days of play time isn't allowed to have an opinion ✌️ /s (don't fire me thx)
gtg eat now