There have been many posts about the lack of differentiation between spells, to the point where many players have stated that they simply get one tactical spell and just keep reusing it over and over, multiple times every turn, in all their battles.

Wouldn't it make sense to implement some type of cooldown (e.g. so that any particular spell could only be used by a specific caster every 2 or 3 tactical turns, or even strategic-level turns), or a hard limit (e.g. a particular spell can only be used a max of twice per tactical batttle)?  This would incentivize players to do more spell research, adding to the "magic feel" of the game, and would reduce the impact of whatever overpowered spells players discover (prior to getting balanced)?

This, of course, is completely separate from/doesn't address the "need" to differentiate spell books, etc. that have been talked about so much, but seems an easy, logical, and useful way to make a quick improvement in the value of research and the use of magic.

i know cooldowns have been discussed before, but not sure why they didn't make it into the game?