>>35904388To be honest, I'd be OK with introducing the literal gods of Pokemon in a "series finale" type game. The problem is that DPPt wasn't a series finale. This left us without anywhere to really go afterwards, but Gamefreak decided to try to take us there, anyway.
Jumping the Shark is usually defined as the moment in a series where the creators run out of ideas, after which they radically change the formula and start relying on gimmicks to keep things going. With this definition in mind, the jump undeniably occurred during DPPt. Gamefreak definitely had good ideas for Gen 4, and there were more than a few things it did well, things that would be sorely missing from the series as a whole if it stopped after Gen 3 (like the physical/special typing split, to name just one). But it is unfortunate that these good ideas also seem to have been Gamefreak's last. In some ways, I see Arceus as an admission that they had gone creatively bankrupt ("We're out of ideas - might as well just make the god of all Pokemon and call it a day!").
In my opinion, stuff started getting really gimmicky after Gen 4. Gen 5's 100% new Pokedex, the dream world, hidden abilities, mega evolutions, ultra beasts, z moves, etc., they all feel to me like gimmicks. Or in other words, ways of shaking things up and putting a new coat of paint on the series, when the true creative core and the spirit of the series went missing years ago. And if we take DPPt as the point where the jump happened, it follows naturally that we started getting all these gimmicks afterwards.
Overall, I still like Gen 4, but I can't say I've had as much fun with any of the games afterwards. And despite my affection for it, there is also no question in my mind that Gen 4 marks the beginning of the end.