This is how I see it as well. Nichols is Glenn 2.0. If he has a good team he'll go over .500 perennially, and that's near impossible for a coaching staff to give up on. (As a fan as well, i never want to re-live 3-15)
To me, Glenn had much better accuracy, a quicker release but suuuuucked in cold weather and under pressure.
Nichols, in my opinion has proven that he can perform in the cold, he can be mentally tough, but there's just absolutely no consistency. Also he's terrible at mid range throws and just plain misses his targets way too often.