So I couldn’t help but notice that with the Starcraft roster, some races are missing out on some roles (no Terran bruiser, no Zerg tank, etc). I doubt this is a genuine reason for Blizzard to release heroes, but I thought it’d be a fun discussion regardless.
Anyways, who do you think should fill the empty slots?
Zerg tank
Protoss tank
Terran bruiser
Terran melee assassin
Protoss healer
Terran support
And please don’t rattle off 3 dozen heroes from your wish list, just pick one for each
For a Zerg Tank, I’d go for another Primal Zerg Hero, perhaps Brakk.
For a Protoss Tank, I’d go with Taldarin, or maybe Selendis.
For a Terran Bruiser, I’d have to say probably a Goliath or BattleCruiser pilot.
Terrans aren’t big on Melee, but maybe Tosh with his Knife?
A Protoss Healer would have to be Rohana in my book. or a Sentry.
And, lastly, a Terran Support would fit Stetmann pretty well in my mind.
Ultralisk 
Not sure. Maybe the aiur zealot variant from LotV? Or perhaps an immortal.
hellbat
predator maybe?
Easy. Raszagal.
If fliers are on the table, I’ll go with a raven.
Otherwise…maybe mengsk? Idk, can’t think of any solid choices other than the raven.
I had thought up an idea for a terran Bruiser, with Swann but a mix of his appearence in Belly of the Beast mission and a Maruader. Kinda more a summoner but then specializes went extinct.
Zerg tank - Izsha (detached)
Protoss tank - Selendis
Terran bruiser - Horace Warfield
Terran melee assassin - Rory Swann in a marauder suit
Protoss healer - Vorazun
Terran support - Magellan (science vessel)
edit: and just to shamelessly plug my Warfield concept…
Torasque (I hope I spelled that right)
Talandar
Well, Blaze is great bruiser but maybe Warfield as a marauder hero.
No idea
Karax
Adujtant (I have even created a concept for her if anybody is interested)
Zerg tank: no idea sorry
Protoss tank: talandar
terran bruiser: warfield
terran melee assassin: maybe the HERC. Is the terran unit with less range, but in the game is a tank. I don’t think there is a unit with melee range in the terran army (except for the scv and the hellbat).
Protoss healer: Karax
Terran support: Swann or stetmann
Sorry, missed an ‘R’
Hellbats have 2 Range. So, not Melee. Like Blaze.
I’m not sure about a zerg tank. Maybe Brakk, maybe some unexpected unit hero. I think Brakk has the best chance, though. Unfortunately, I made mine into a bruiser.
Khastiana definitely for a Starcraft tank. Talandar is a good option as well. (update pending for my Khastiana).
For Terran Bruiser, Rory Swann is a good choice. (update pending) Otherwise, Tosh would be a good choice (post pending).
For melee Assassin, I suggest Stone (update pending), a friend of Nova’s who could use her Monomolecular Blade.
Protoss healer is a definite Rohana (update pending).
I’m not sure for a terran support. Maybe we could see odd Matt Horner concept?
Ultimaton (the Ultralisk hero idea they dropped in the early Alpha)
Kaldalis
Kev “Rattlesnake” West or Rob “Cannonball” Boswell (Tychus Co-op Maurader and HERC, respectively).
I don’t think there are any characters that really fit for this. The whole point of Terran combat is to keep enemies at a distance.
Maybe a Hellbat, though I think that would make for a better Bruiser.
Rohana
Stetmann or Bill “Pearly” Bousquette (Leader of Raynor’s SCV corps)
Zerg Tank: Hmm i honestly don’t know outside the Ultralisk which is currently used by Kerrigan and a map objective, perhaps a Brutalisk? but then again they’re more Bruisers than anything.
Protoss Tank: Khastania as an Immortal is a legit tank unit for protoss in Starcraft i even wrote one im midly proud of, other than that i’d say one of the Royal Guard that show up in early LOTV cinematics that get a dumbed down version as a Zealot variant (halberd and shield basically).
Terran Bruiser: Honestly hard to tell, the Herc from Tychus’s crew could fit here but he also fits the Tank role a bit too much, a Warhound unit can work possibly, a Hellbat could fit this role but might overlap with Blaze a little.
Terran Melee Assassin: Very hard to figure whom as only Nova with her special sword was shown to be there melee fighter, before then closest we ever had was the Warhounds melee and the Firebat, so guess Warhound can fit his role again like Bruiser just squishier lol.
Protoss Healer: I’d say maybe a Sentry with elements of the Shield Battery added in, Protoss generally dont heal but prevent damage or buff you up as seen with Tassadars gameplay basically, lack alot of knowledge to even attempt finding a unit or name.
Terran Support: Science Vehicle straight up can be a support unit with Irradiate as a burning rage style buff and Defence Matrix to reduce damage, Stettman could be this but given his gameplay in SC2 he was basically a Super Medic, the Raven could potentially use other abilities in there tool kit to become an aggressive Support as well.
(Bonus point Project Haven arcade map has ideas for heroes that could be made fit into other concepts to help out)
Zerg Tank: Like other said, Brakk would be a good choice, but I feel he might be difficult to visually distinguish from Diablo, so maybe Kraith (or Dakrun) instead.
Protoss tank: Talandar (in his default body) would wrok IMO
Terran bruiser: Maybe a Marauder? Could be Warfield, I guess (or Swann, since he was pretty much a heroic Marauder in his campaign appearance)
Terran melee assassin: no idea… Valerian has a sabre, right?
Protoss healer: 'toss don’t seem to be very into healing, but I don’t think it would seem out of place for Rohana (as has been suggested a few times)
Terran support: I agree Stetman could feel this role, or maybe Swann (if he’s not the bruiser)
Using Swan with a Marauder skill-set would also fix the issue of the Marauder just being a Firebat in a different color, which neatly avoids looking to similar to blaze.