I would've rather the super be cut down to 75% duration (total with the exotic) than to lose the regen feature.

Imho I just think you are overreacting. There are mods you can use like energy converter to get your super back.

There sure are, but I don't want to use those. I'd rather save mod slots for other things. I liked how Geomags functioned. It's fine if you disagree, but I liked the functionality of those specific exotics, and I think it's a poor decision to change them.