I agree it would, but it does in Skirmish too, and their stated goal was every class available for everyone, so I wonder why they have one rule for the more casual modes and another for Skirmish.
As someone who spends a lot in Skirmish I'd love to disagree with you and say it's perfect but I can't.
Even though my clan usually limits itself to a max of two cavalry units, I am not all that sure it's clever. Even in Clan vs Clan matches with more coordination Cav can be pretty strong against spearmen.
But I want to give some reasons why having instant acces in Skirmish is a good thing:
-Limited lives. In TDM and Siege you always have the chance to grind up to a high tier unit as long as time is left. In Skirmish you hav a maximum of 3 lives per round. So playing or loosing a high tier unit is a lot more impactful.
-Snowballing. Snowballing is always an issue but when looking at how strong cavalry can be, it would be horrible to only give it to the already stronger players. Different to Siege and TDM a single player can be a lot more impactful.
-Team composition. With all units accesable you can always re-use your gameplan and strategy.






