>>47144696GF has said that they want certain features to remain within a generation to make it a "defining feature" of that part of the Pokemon mainline series. This is so then they can continue to add new things into the games without it getting stale. Seasons, in this case, are the defining feature of Gen 5.
I, personally, disagree with this reasoning, but I think part of the reason why they're thinking like this is because of a lack of available development time. GF has had very little time recently to develop and release mainline games compared to the past (Emerald and Platinum each took two whole years of development, and Diamond/Pearl had to be delayed) while now Game Freak only had about two years to make Sw/Sh concurrently with LGPE.
In addition, GF has always had trouble transitioning to new hardware, but once they have their feet wet for a while with a single platform, the dev team usually hits their stride. Take Emerald (or Drill Dozer) for the Game Boy Advance, or Black/White 2 for Nintendo DS. I'm still baffled that BW2 can run on the original DS models and not just the DSi. The games are very polished in terms of presentation, and it really shows. I'm excluding USUM because it was not directed by the typical staff - it was handed over to Gear Project (GF's second internal team) to give their new devs a chance at making a game.
Regardless, Game Freak has been continuously hampered by a lack of time due to TPCi enforcing a release schedule, and it's hampered the quality of the games as a result.
