D/P/PT which would be otherwise great games were partly ruined by that freakin stupid frame rate, platinum is playable but dear god the original diamond and pearl... especally after the fast 3rd gen ill admit even the third version gets tedious at times and i find myself resulting to turning animations off
Also HG/SS despite having a smoother interface compared to diamond and pearl was very tedious at certain times such as the team rocket radio tower takeover, and pretty much the entire Beginning until violet city(although imo the game didnt really get interesting till goldenrod) due to gold and silvers already slow pacing mixed with the slow 4th gen speed.
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Definitely Black 2 and White 2, if we're talking in terms of story. Team Plasma actively does nothing and has few significant appearances until after getting the 7th gym badge, and then it's over almost immediately afterwards. This also made Colress a waste of time since Ghetsis appears immediately after he supposedly turns out to be the leader. Earlier on it's mostly a repeat of Black and White, with you following the same route and it's really tedious.
But otherwise Diamond and Pearl for the reasons you said, though I think Platinum improved it.