I think the prevailing opinion about Crysis 1 is that it's kinda a pig of a software package. Over time, optimizations can be made to do the same work with less bloat.
what? bloat!? cut the number of trees in half perhaps?
the people who thought that crysis 1 was "unoptimized" just don't get pc game graphics in whatever context possible (scale, physics effects, lighting etc.).
the first crysis was just hardware bottlenecked, too far ahead of it's time. (the fact that the performance does increase with each generation of hardware is a clear evidence of that).
what we get is cryengine3 where there're no chicken or sharks to play with.