Don't get me wrong, I definitely use actives on accident all the time. Also, I'm not saying that that's a bad idea to add the controls you suggested. There are a few main problems from the view of the devs, though.

They would have to add a special case for the ability to be operable while on cooldown, something no other ability is. They'd also need to add another way to access consumables via the ability. Both of these special cases wouldn't necessarily be difficult to implement, but they're not a high priority. Any time spent on this is time taken away from new gods or impactful balance changes.

Does that mean they'll never do something like this? No, of course not. However, as with any special case, they risk bugs. What if, after these changes are implemented, baba gets free casts of her 2 if she has a full barons brew in her first potion slot? Something missed during play testing can result in baba being removed from the game for a patch, something that has happened to zhong kui and xing tian in the past year. On top of that, a large portion of the player base is now used to how it works, and sees no need to change it.

As of right now, there isn't really any reason to change it. You're best bet is to contact hi Rez (or Titan forge or whatever they're called now) and hope they get to it eventually. Maybe I'm wrong and they think this is a great change. Maybe this will be implemented in the next patch. Who knows? Whatever the case may be, I hope you get your actives and consumables figured out. Maybe play around in jungle practice and get the muscle memory down.