While a Chao-less category sounds like a good idea, I don't think the reason for one should be because we'd need to take into account how long to obtain and upgrade the Chao. After all we already don't account for how long it takes to get to a high enough level to max out your character's speed.

I'm new to the game so I don't know how much it helps but if being able to have 5 Chao with you instead of 3 helps you run significantly faster then I do think we should have 0-Chao, 3-Chao, and 5-Chao categories. Especially if being able to equip 5 Chao at a time is locked behind real world currency. Which I assume is what you mean by "buying dlc."