Michael Shannon superman would have been something to look forward too. Heck! He would be an awesome lor zod.
As for everything else i don't particularly have an opinion. It's not like we need some oscar worthy performance to be superman . Not that i would mind someone absolutely unbelievable playing superman.
Didn't avengers age of ultron have many dream sequence with darkforshadowing including everyone dieing because of thanos? Did it actually happen? No,it didn't. The only person that died was ironman. So, a dark foreshadowing =/= what will absolutely happen. We had two dreams sequences in both ww and mos. Clark was swimming in skulls remember.did this happen for real?