Nova is effectively a sniper with a cloak. Her psionic abilities don’t really do anything in practice.
Tosh (and most spectres) rely more heavily on their psionic powers, with abilities like Consumption and psionic lash that attack their target’s mind directly.
The shared cooldowns is unworkable, if fully overlapping. Perhaps have “secondary” players get a partially different Talent tree based around supporting functions, one basic ability to themselves, one shared basic ability (charge-based with independent uses cooldown?), then a third basic ability defined by 1st-level Talent?
Maybe the Mind Control effect would be the exclusive Basic ability for secondary players, while the primary player would have it as a Bribe, competing with buffing mercs and some strong waveclear bonus? This makes it so that three players in Ulrezaj gives instant Siege Camp clears immediately, while freeing the Talent for the primary player to buff them, thus making up for macro losses from bodysoak difficulties by ramming a three-person CC powerhouse with boosted mercs down the third wave.
Then the shared ability, charge-based as it is, needs to be something that wants bursting and target coordination, but isn’t entirely crippled on its own. Perhaps a stack-based version of Malestrom that builds up with each overlapping use. The first is a Blind, the second is a Silence, the third is a Root/Stun, with the duration being longer than the use cooldown so a lone Ulrezaj can chain them together. Multiple players split the effects, so that they have to coordinate to get a full disable, but conversely skip the stacking, so you can immediately completely disable, or Silence to start the fight. Or peel with a Root.
The thought is to have a three-person Ulrezaj meet a breakpoint where they’re able to walk up to almost any situation and immediately warp the way it goes, with teamfights immediately having whatever’s most troubling taken away for a moment, waves being abruptly switched around, merc camps being immediately sent off and structures facing huge amounts of siege damage. You can deal with it, but have to outlast Ulrezaj instead of just bursting them down. They’ll turn off your burst, whatever it is, if they know what they’re doing.
Of course, killing this Ulrezaj case means a vast swing in the game’s outcome, because it immediately takes three enemy Heroes out of the situation and gives you the XP for three Hero kills. If your team has versatile sustained damage and you know how to avoid dying, you can get a ton of value. So there’s several layers of risk to stacking Ulrezaj, not in the least being that you’re relying on winning off massively exaggerating one toolkit instead of getting three different toolkits in its place.
I vote for zerglings. Make em sort of like TLV in sence they are separate. Or make one Alpha of the pack and the rest its minions.
Let them be bruiser. Their strength is survivability by constant teamfight rotation, but they cannot go 2 far from each other. Good vs warriors.
Weaknesses: aoe.
Talent idea: shield when one of them dies. Ult: spawn more zerglings or 1 lurker.
Terrans have a full roster as-is… and more stealth is a non-starter for me, so Tosh is out - as much as I loved the character. I could be persuaded to vote for Mira Han, as I find her to be a compelling character who could yield an interesting play style.
And as much as I love the idea of an Overmind hero, it would feel a lot like Abathur.
'Toss are lacking a proper support/healer, so my vote goes to Karax.
If Karax is going to be a healer better dont even bring him to the nexus. The best part of playing Karax in starcraft 2 is his barrage of low cost solar beams with global range and decent damage.