reading a thread on TL, I had an interesting idea for ultras. It doesn't sound too OP when i think about it.
How about, keep them exactly the same as they are now, but give them the ability to move while burrowed. Not even needed to be researched maybe since they are tier 3 anyway.
The cool thing I'm imagining in addition though is that although they would be able to move while burrowed, you can see them in the ground as they move. they are, however, invisible when staying still just as they are now and the trail that you see as they move while burrowed will take a short few seconds to disappear. This would make sense flavor-wise since ultras are so big they cant hide while they are burrowing.
In regards to detectors, although you can see the ultras moving underground, only when a detector is around would you be able to hit them. Much like how it would be for DTs coming towards your army. However, ultras would have to unburrow to attack unlike other cloaked units. Finally, as they unburrow, one of their attacks procs near-instantly to the nearest unit if in range. (with a different animation to show the ultra exploding from the ground)
Now here's the two things this would solve: everyone seems to consider ultras as being useless mainly because they die before they even reach their targets. Not only that but second, they get trapped behind even your own units because they are so big which contributes to them dying so quickly.
By being untargetable without detection then you can expect or rely on ultras not dying before they reach their targets.
By moving while burrowed they can be maneuvered without running into everyone's troops.
By adding this unique noticeable version of moving while burrowed you both help improve the flavor/influence of burrow as race trait as well as distinguish the ability from being criticized as just an ultra's version of a dark templar ability.
Finally, I think we can all agree that ultra's being able to do this would see them being used more often.
I'm also imagining how understandable it would be in terms of all zerg ground units having some type of usage of burrow:
*All ground units can burrow
*drones and queens burrow to save their asses from attack (common target)
*lings burrow, upgrade into blings to burrow+ability: explode while burrowed
*hydras burrow, upgrade into lurkers to burrow+ability: attack while burrowed
*roaches burrow, upgrades to burrow+move+ability: regen, physical stealth moving burrow unit
*infestors burrow, upgrades to burrow+move, magical stealth moving burrow unit
*ultras burrow, upgrades to burrow+move, noticeable massive moving burrow unit
This was just an idle thought at first, but I'm seeing no downsides to this. They are already mad expensive, this would just actually allow them to be used competitively while not overpowering them. The idea of a stealth ultralisk sounds OP, but make the stealth obvious enough to the point that it's just a way to get them to get attacks off EVER while giving every race even more reason to care about detection and it seems solid to me.