A well known example of a decent sequel that got bashed for being too similar to its predecessor is Hangover 2. Even though it would have been pretty funny on its own, it was way too similar to the original to not be compared to it, which led to some critics viewing it as worse than it really was.
22 shamelessly makes itself similar to the original to avoid this problem, but does actually expand and differentiate itself enough to make it worthy of standing on its own.