Too much personal opinion in here
Generation V is seen as a major departure point for the series. While the Generations preceding it often adhered to the formula [[Generation I]] had established, Generation V did several things that differed. Setting itself in a region where Pokémon from previous generations could not be caught, putting out dual sequels instead of a single third version, and using a dynamic camera angle with continuously animated Pokémon sprites in battles. While some of the changes seen in Generation V may have influenced future titles, [[Generation VI]] saw further changes, thus establishing with fans that each generation from this point forward could contain features unique to that generation which may be dropped in then next. Generation V for example is the only generation to date that utilizes [[season]]s.