Super Mario Sunshine is not only NOT a worthy successor to Mario 64, one of the best Mario games, it's also a bland game in its own right. Almost everything about that game feels clumsy, from the mandatory, long, tedious objectives, to the ill-conceived watergun, to the story, to the voice acting, to the level design. It doesn't have a bit of the freedom that Mario 64 offered and its platforming is inhibited by controls that are inferior to those in its successor and predecessor. Every objective feels bloated.
Though it is not as bad as DK64, it still reminds me of that game in that the whole thing feels like busywork. Tedium incarnate.
Oblivion is the worst Elder Scrolls game, and it follows arguably the best. It's a very similar situation, actually; Morrowind, like Mario 64, is a defining moment in gameplay history and a high point of its series. Oblivion is a clumsy mess that hardly feels like it belongs in the same series.
Morrowind had a less than perfect skill/attribute leveling system, but it was still relatively manageable and you'd rarely find yourself permanently underpowered against enemies. Oblivion, due to its nonsensical level scaling premised on making the game more challenging instead of letting the player feel more powerful as a reward for their hard work, gimped your character if you didn't prioritize certain skills.
There isn't half as much depth to the story or the writing; most of the quality lore comes from Morrowind, and while that game at times felt like a good sci-fi novel, much of Oblivion is written like an undergrad's enthusiastic but embarrassing submissions in creative writing class. The story isn't exciting, which would redeem it, and the characters feel flat.
I love the soundtrack, and the world is nice enough, though even there it's not half as well-designed as Morrowind and Skyrim. The quests are fun. All of this makes me think that if Oblivion were remade in Skyrim's engine, it would be worth exploring again. But the gameplay itself is so poorly designed as is that I question revisiting Cyrodiil when two adjacent provinces have provided me with so much more joy and wonder.