It made more sense, yeah, but that was when BIONICLE was constraction. Some people obviously want to keep the Kaita in G3, so there has to be a compromise.
I had some ideas, but StSc's suggestion of not using actual combiners is a better one.
I think there could and should be a balance of both. The Toa have always been about clever solutions to their problems, but a hefty serving of brawn accompanying the brains can't hurt.
You're thinking way too narrowly. If a six-member Kaita was used as a "last stand" against a monster, it would be just that - a last stand device in the final year of the first arc. It wouldn't be used over and over throughout the arc or later arcs - that doesn't even go along with what was original proposed here. I was using that element of PR to demonstrate my point, not proclaim it a model we should follow to the letter.
Keep in mind we're building G3 from the ground up, so we can impose any rules necessary to keep things sensible. In G1, the Kaita could only remain formed for as long as the Toa maintained concentration. It could be a similar situation in G3 to explain why the Toa don't just use the Kaita for everything, as the bigger they go, the more difficult it becomes.