Copy HOMM3's skill system for shop rolls?

In Heroes of Might and Magic 3, at every level up you're offered a choice between upgrading one random skill you already have or instead gain one random new skill (you're told which skills are those before you make the choice.)

So, what about something similar for the champion shop? E.g. of the 5 champions in the shop, 2 are copies of champions you already have and 3 are of champions that you do not have.

Also, what about an "heightened reroll" option? I.e. you pay double, but you have an increased chance to get champions that synergize with the ones you already have.

Why do all of this? Because it would help alleviate the issue of often not being able to build a teamcomp because of a too large champion pool. It would also increase the strategic aspect of the game, in case anyone still cares about that.