Yes, true. But Ninjago had plenty of swarm villains. This G3 will only have 6 total per wave (I think). You got to fill in those extra gaps somehow, so you'd fill them in with villagers (who would probably be in dire need of saving, like in a cage or something). You wouldn't have that many extra, though, so I do see your point.
So do I, I even drew I picture in another topic, though that's beside the point. I'd figure these "energy toa" would be included in some sort of power gimmick, like Ninjago's spinners or chima's speedzorz, rather than an actual set.
This is true, though I would still think regular minifigs are valued more highly by the Lego community than shorter ones.
One other point, however, in defense of long-legged minifigures are that those legs have prints. Short legs have not had prints Except for one small exception- Bart Simpson has a slingshot printed on the back of his short legs (which doesn't even matter when it comes to bionicle G3, 'cause not even regular mini-figs have back leg printing).
This brings of the issue of uniformity throughout: in essence, if you have a very detailed body, arms, and mask, would it not look very strange to receive little to no detailing on the legs? You could cover them up with a skirt piece, but not for every mini-fig.
I'm, honestly, really interested on our response to this last one, since you drew the toa and all.
Just saw this now.
What I think @TeslaEffect
meant was that, in battle packs most specifically, lego never really sells the main hero or villain, there.
You could do some sort of swarm enemies rahi matoran-cult thing for the villains...
But the heroes would have to be matoran/turaga. AKA, all small legged characters. I don't think a lot of people would like that.