YUNoJump

It's power creep as it is now, although player power creep has kinda already gone way out of control. On the other hand, I think I prefer Overguard-based survivability more than just "90% DR" survivability; maintaining Overguard is somewhat more involved than "press 3 every 40 seconds". And as someone above mentioned, 100,000HP is mathematically similar to 1000HP and 90% DR. If providing Overguard to a whole team becomes a common ability type, I'd like to see squads where they rely on that instead of everyone just bringing their own DR method. Warframe has a distinct lack of actual teamplay beyond "4 dudes killing stuff in the same general area"; relying on team-based Overguard could be a first step towards enhancing teamplay and cooperation. The last time Warframe had actual teamplay was Trials and maybe Railjack 1.0, but they're long gone.

They actually addressed it in this update's patch notes, they changed the UI a bit and they should have better changes coming soon.

The thing that gets me about the "no enemy score" condition is that it isn't really how you play Index, its an unnatural method. With the ally bots it's natural that the enemy scores a bit, but you don't need to worry as long as you score more and keep the timer up. Nightwave is partially designed to make you interact with parts of the game you don't normally interact with, so the weird side condition isn't necessary.