ToME: the Tales of Maj'Eyal

I had a weird gaming experience with my first Arena Master, who is a summoner. I unlearned every summon skill to lv.1 right after I used it, and learned it back before using it again. In this way I was capable of actually possessing some 10 or 20 more skill points than I was supposed to. I guess this is a way of playing that should be discouraged. Admittedly, it isn't an attractive way of playing, since it takes too much patience. But if someone makes a module or a tool to make unlearning and learning only one or two hotkeys away, it can be more tempting.
To discourage this, maybe we can make character upgrading take one or a few turns, depending on how much change was made. It make sense that the character need a while to fit the change of his capability.
Sure, it's a minor detail. But I believe some noticed minor details can make things seem interesting. And the detail won't do much harm. It won't harm game experience. Players might will have one or two experience to realize that upgrading amid battles is not a good habit, but as long as their characters didn't die for that(which is not likely) the experience won't be annoying, and changing the habit won't take much trouble.

A far more common case is leveling up mid-fight, distributing skill points, and then fighting on. This proposal would punish that and a sudden change would confuse players. What you're describing is more akin to a fringe case (and a better countermeasure would be just implementing a cooldown limiter on making skill changes or something).

I think I suggested having a cooldown reset when it was leveled, but people said it would be too penalizing for people who leveled up in battles as well.

I wonder if you could have a skill gain one turn of cooldown(not permanent cooldown, temporarily being set on cooldown) for every skill point that's put into it? Or even just have its cooldown set to 1 whenever its skill level is altered? One turn of cooldown will basically never kill anyone, but would totally wreck this strategy.