Aarklash : Legacy

I'm thinking that from a gameplay standpoint he is the weakest of all the NPCs, by far. So much so that I'd even say he's pretty much useless, even if that's a bit harsh.

All the other characters have something going for them, maybe some less so that others, but still have at least 1 skill that rocks in a certain setup while still being able to fill their main role without gimping the whole operation.

I just can't see any redeeming qualities in this guy though, enough to include him in any party. Not only his skills are very situational, they are inferior to the alternatives.
For example, the best idea I've managed to come up with was maybe to try using his "reverse healing" skill upgrade on one of the golems so I could nuke them both at the same time with AOEs, possibly speeding up that fight. But I'm not even sure that would have worked since that golem's "turn all damage into healing" ability is a passive. So in the end I decided against it, since Wendaroo is clearly more powerful a healer and also has a skill that can steal that crazy buff from the phys golem.

So can anyone make a case for Motcha?

Yeah, Motcha's simply inferior to Wendaroo. I think if they really want to keep the healers feeling very distinct, like they did with the tanks, they'd need to give Motcha some damage abilities or something so he'd be something of a healer/dps hybrid. In his current state he's basically half as good a healer as Wendaroo, with arguably similar miscellaneous utility (I think Wendaroo's better even at that but that's debatable). The only use he has is making the game harder for a second play-through.

There's little doubt that Wendaroo has higher healing output - especially burst healing - but I think you're underestimating the utility of his heal negation. Its not so great in boss fights, but I generally found boss fights easier than many of the regular fights. With Motcha you can just ignore healers and put the debuff on the highest damage/control threat, and the enemy healers will help you kill it. Control immunity can be useful in certain situations as well.

My party included Knokka and Nella, so I wasn't lacking for heals and chose Motcha over Wendaroo. If you had Bo Lahm tanking and weren't using Nella, I can see the extra healing from Wendaroo being more important.

Also, unlike Wendaroo, he can do damage. His heal can target enemies, so if you put the heal negation on someone it acts as a decent single target nuke. I also built so that it was instant cast and could block support and controls spells, which means you can use the combo as an interrupt as well. As far as I recall, Wendaroo offers nothing like that.

His boucing heal ability is pretty phenomenal too