Exactly, "pretty good" does not equal great. You add to one aspect - you lose in the other since they are all interdependant. Besides, all AC games in the series were quite repetitive.
This is a bold claim. Or maybe i'm misinterpreting what you said, but
To me it's nonsense so i'm suggesting you bring some hard facts to back it up, otherwise it's just empty words.
Why on Earth does improving graphics necessarily lead up to worse gameplay?
Nonsense.