Right now all three of the heroes have fairly bland abilities. For regular abilities you've got damage in an area, damage in an area and... damage in an area. Zed's ult is press button for stats, Bunker is aggro and invuln (which is a little interesting) and Blaze has... damage in an area again. None of these are all that fundamentally different that I would want to play through the game again to try different abilities, and none of them particularly alter your playstyle. I think that's a shame, as replayability is a core value of a rogue-like and variety is the biggest factor in replayability. I hope Amplitude comes up with some wild heroes that radically alter how you play the game, like they did with the Endless games.

I have some ideas for some interesting heroes.

A hero (Broken lord maybe) that constantly loses .5% HP/second down to a minimum of 25%. While at or below 25% they are weaker. However, every time they kill an enemy they gain HP. They also have very strong abilities which come with the downside of costing HP to cast. This heavily incentivizes a very, very aggressive style as if you sit around between waves too long your HP will drain away.

A hero that is actually a swarm of small insects. Normally they all group together into a humanoid form wearing a robe, but they can disperse across a room attacking everything in it and becoming untargetable/invulnerable. Good for people who want to leave an AI to guard and not worry about them dying.

A hero that gains substantial power and has zero aggro while in rooms with the lights off. They have either a ability that pulls enemies towards them (to drag them back into the darkness), or they can leap around. You get to be the monster in the darkness.

A hero that once per crystal door can create a turret hardpoint to place a turret in.

A hero (Sophon maybe) that can upgrade themselves at artifacts instead of selecting a turret to research.

A hero (Riftborn maybe) that can freeze all enemies on the map in time for ten seconds, but also making those enemies invulnerable for the duration. This way you can reposition or build turrets if you get overwhelmed. Good for new players.

A hero that can enter a sniping mode where they are long range and can move the camera away from themselves but cannot move while doing so.

A hero with four arms that can fire two different guns at once.

A hero that can teleport to beacons they place around the map.

A hero that has pets or minions that they can direct around.

A hero that can call down a bunker nearby heroes can hide inside if they might die.

If anyone thinks of any others, please chip in.

I agree there's not much difference between the heroes at the moment. Also your post reminds me that nothing in this game yet really feels like it's in the Endless universe. I'd love to see characters from races in EL and ES. (DotE didn't have a lot of species in common with the Endless universe either, but at least it was set on Auriga and IIRC was the origin story of the Vaulters, so it had that connection to the universe.)

I'm also mixed on whether I'd like to see the Operator mechanic back. In DotE that at least created two strong class distinctions: regular guys that did combat and operators that stayed with the generators and acted as a turret. It would definitely need some changes (I hated that stepping foot outside the room would cancel the operating for a whole turn). But having a support / operator class that gives passive bonuses to generators and turrets nearby would be pretty cool. (I noticed that there's a "wit" stat, I'm not quite sure what it does other than maybe make repairing and upgrading turrets faster.)

Edit: Speaking of unique hero powers and fitting in with the Endless universe, I want to see a Horatio hero this time pleeeease (a suggestion I made for DotE four years ago). :)

Awesome ideas stealth is always fun having an alternate ultimate while in stealth would be cool! I just love super complex characters. If you’re in stealth the ultimate would change to what you said as the number #2 ultimate and when not stealth to an electric cone attack dealing electric damage. You’re exactly right each enemy killed using ultimate reducing cooldown is awesome way to reward the player but should be done from behind since this character is gonna be FAST. Adding to the passive, dark rooms could increase your speed damage and critical. I’m thinking of Esseb Tarosh from DotE or a Blur hybrid for the appearance.

The station spectre Unlocked after reaching reactor on hardest difficulty (Combined most of what everyone has said into this character)

Lore

This character has bonded with the crystal and feels perpetually pain every time you are sent back to the saloon.

Pistol User
Active - Shadow Walk Stealth for 5s (while hidden 5% speed bonus, no aggro, leaves a stationary holo hero shadow behind but you receive 10% more damage from enemies. Activating again causes you to teleport back to holo hero shadow destroying it as if the stealth timer ran out)

Shove (while stealth) - forward short range blink teleport damaging enemies as you teleport through them)

Shove - Enemies hit slowly take DOT damage. Bonus from behind.

Ultimate (while stealth) - No Escape! Temporarily removes power from room shutting doors for 10s

Ultimate (normal) - Shadow Storm attacks in cone dealing electric damage, enemies killed from behind give you more Ultimate charge.

Passive - Increase Critical chance, Speed, and Damage when in dark room by 10%. For every dust increase speed by 1% When in dark room refresh chaos stacks and lose 1 every minute outside. Start with a total of 10 stacks of chaos. When you reach zero stacks tigger a reinforced wave and lose passive bonuses.

Hero upgrades

Close one - When below 30% HP trade places with highest HP hero activates once per district

Terrify - Enemies in dark room take 5% more damage deal 5% less and do not target you.

Eternal - Can use dust as medkit

Hunger For Power - +50% attack, when Chaos reaches 0 destroys crystal

Move like they do - when in crystal room every 10 seconds you are immune for 1 second.