I liked Banjo-Kazooie better than Banjo-Tooie. It had such a great mysterious, forboding feel to it that Tooie lost. I think Tooie over-explained things to you.
Let me itemize a bit:
Grunty's Lair vs. Isle o' Hags:
Grunty's Lair was labrynthine at times. You'd wander around, find weird stuff, have it become apparent - without someone telling you - and get pleasantly lost for the fact that the levels aren't always obvious before they were opened. And Grunty's rhymes in the Lair? Perfectamente.
Threats of the levels:
There was a lot of stuff that'd inspire fear (a way to tell a good threat) in the player, from long underwater passages to the shark who'd nip at your feet to the fact that dying would mean you'd have to restart your note collecting (dying MEANT something!) to the fact that really long falls could actually kill you (I loved that! Click Clock's tree was huge - and it felt that way!)
Finding Jiggies
Jiggies were quite mysterious in the first game. You'd be playing along and just find one sometimes, as opposed to having each one be obvious from the start.
Banjo-Kazooie had more of an impact on me than Tooie, though I still hold Tooie in high regard. Hailfire peaks came very close to matching that threat level, Grunty Industries had a great mysterious, infiltrative feel, and all of the secrets and details would've been so great-- if Jamjars didn't announce and explain absolutely everything.
And then there's the fact that you could get all of Kazooies great moves, ditch Banjo and fly around the level... (Banjo's so useless!)
...Oh yeah, and Jolly Roger's Bay... THAT, I think, was the reason I bought the game. I didn't know that you could freeze the octopi, and I didn't find the warp pads underwater. So it had a great underwater exploration thing going for it.
Oh? Donkey Kong 64? That's right... I didn't much care for it. They tried to pack too much into too little space. I've never been a fan of HAVING to go aver the same level five times over. If I do, I'd like it to be of my own accord, thank you.
Go Moon!