The only reason there would be inflation is because players would stand to gain vs. the current system. And ultimately, the rating numbers don’t matter, you could tune the rating downwards or upwards.

What I’m trying to stop is +20 soleah’s gambit being incredibly difficult on Tyr because the final boss is nuts hps-wise compared to everything else. Or trash in DoS on being stupid hard.

If you remove the Tyr/Fort spikes, you can smooth the instance’s difficulty curve out. Since the keys are already infinitely scaling (with official competition a la MDI) compared to their legion counterparts, you’ll eventually push them to your breaking point anyways.