First I want to start by saying I saw this game when it was called "Raiders of the Broken Planet" and it looked quite interesting. I didn't get the game then and those reasons are an entirely different subject but as it's remarket to "SpaceLords" and offered as a free game I jumped at the chance to give it a go.
I believe the developers from MercurySteam have done a great job of it in many ways, it indeed takes time to get used to and glad Antagonist takes until level 10 to be available so at least players get a feel for it before being the enemy.

That being said I am new on xbox one with my username here as my gamertag and have enjoyed it since I started playing 4 days ago. I am level 17 about to reach 18 and since I reached level 11 and could contribute to The Aequilibrium Wars I've tried out antagonising as much as I can and feel it works well but definitely still needs tweaking and here's a few ideas how and brief reasons why.

1) Make every mission have an antagonist no matter what. I don't know why this isn't a thing already but it should be. Reason being that it's advertised as a 4v1 shooter so that rogue element should always be present, sometimes it won't be a player because the game can't find an antagonist so a comparable A.I. should be in every match.

2) Antagonist does need a slight buff to their damage resistance, especially if your level is 40+ below your opponents, getting hit from a strike from one is a death sentence because you lose too much health and can't evade or react to it. Let alone trying to make an entire team lose 16+ lives.

3) Antagonist also NEEDS additional objectives especially in circumstances like #2, if you can't kill your opponent then a couple of extra objectives could make it more fun as an antagonist and for lower levelled ones more fair. This should be a MUST for boss levels with antagonist objectives being harder to match that of fighting a boss, I'm yet to face one on a boss level but having to defend yourself from an antagonist AND fight a boss when their objective is to just kill your team... seems too easy and not fun to me.

4) Give each mission an option to be a specific antagonist choice, like on shock it should be Kuzman and anyone playing on that mission as an antagonist should get bonus rewards for sticking to the mission character as a trade off from picking a counter. Also gives new players a chance to try the character out before they earn them so when they do, they're going to be more efficient as them in ALL other missions.

These are my most contributive thoughts and would love to know what players think and if possible Devs tooX