YES, game franchises do affect how games are reviewed, specifically by coloring games with that franchise's inertia.
FF XIII is an obvious example, but XIII-2 is actually a better example. XIII-2 was mechanically superior to XIII in every conceivable way. The cast was likable, the story was coherent and willing to play with it's own ideas, and there was none of this corridor business in the level design. XIII-2 was everything I could reasonably expect in a Final Fantasy game.
I feel the review scores were harsher than it deserved because Final Fantasy was struggling at the time to recover from XIII.
Another good example: 3rd Birthday.
Taken on it's own it's a solid 3rd person shooter for the PSP if not better. The mechanics are solid and the overdrive mechanic in particular had the potential to create a tactics-shooter hybrid. Alas, 3rd Birthday was supposed to be Parasite Eve 3, and there's no way a shooter with an incoherent story and bland characters can fit in a franchise with the ridiculously well written Parasite Eve. It got reviewed reasonably poorly.
It's like 3rd Birthday deserved two scores; one for how it stands on it's own (rather well) and another for how it stands against the series it sequels (incredibly poorly).










