Just found this post, figured I would weigh in, because I do find it an interesting concept.
I think it would make more sense if it was not a CD specific to that type of ki attack (tri-beam in example), but to all ki attacks. If you use tri-beam your energy or ki or whatever you want to call it is depleted, and you can’t use ANY ki attack for 5 turns. However, if you used a basic ki blast or laser eyes you would have no CD or maybe just 1 turn of CD. Once the CD is done, you could fire off ANY ki attack.
The idea of powering up an ability is neat also. Both in this context of doing something to lower the CD, but also just in general. Something where you can “master” a move in time, giving you different alternate versions of the move. Perhaps that early game move becomes rather weak and useless later, but if mastered it can contend with the bigger moves late game. Would need to be balance of course. I have sort of seen this in dbz games before where there are a bunch of differently named kamehameha attacks hou learn as you progress to keep it relevant later “ultimate, father son, x100.”
I also think transformations having a much higher cost at first, and once you have ysed them enough or done something they have the normal cost, and over time mastered to less cost.
There is a recent topic discussing alternate versions of ki channel, but also branched into other moves and even fighting styles here: