Mario 64 is a hard game for many.
I had many friends (all even the ones who game quitte allot) who played that game and never finished it 100% and they quit playing while I easily beat it 100%
same goes for mario sunshine and the 2 mario galaxy titles.
There are allot of lvl's even though you had to repeat the lvl's in different ways to find multiple stars.
There was allot to do and plenty of variety in my opinion if you managed to get a certain amount of stars wich in some cases was pretty hard to some since only hard stars were left to unlock new doors.
same goes for zelda ocarina of time, I love the zelda 3d games more than the older 2d games.
I you find mario 64 and zelda oot bad I won't argue just can't imagine banjo kazooie etc being better games wich I also have played and own.
I think for me personally, the transition to 3D for classic 2D games just didn't work well. Sonic, Mario and Zelda (even though it was quasi-3D, go-anywhere to begin with) didn't feel like Sonic, Mario and Zelda anymore. Sonic and Mario in particular were games about precision jumping and timing. With the clumsy transition to those early 3D games, I found myself constantly missing what/who I was trying to jump on and because of the lousy camera angles, takings hits running into enemies that the camera hadn't panned around fast enough for me to see.
To this day, I don't play 3D Mario titles and I thought the Galaxy games were pretty blah as well. Sunshine I had some fun with, mainly because the gameplay focus shifted from precision platforming to using the squirt pack to clean up the ink. When Nintendo and Sega decided to make 2D entries in these franchises (New Super Mario Bros. and Sonic Anniversary respectively), I was all over it.
Banjo-Kazooie and Tooie-even though they too were 3D platformers-was a new franchise with no previous entries to compare to. They also had some fun gameplay mechanics such as Kazooie running fast with Banjo on his back , digging holes and using Kazooie to drift when you jump from a high area. The game also had a special charm all it's own.