Yeah, I've generally preferred the games that let me explore a lot more. Stuff like Mario 3, or my personal favourite 2D Mario, Mario World were so chock full of things to discover that I honestly enjoyed that more than beating the game. Mario 64 was the same way. The first star in most levels is pretty obvious, but there were very few that you couldn't go off the rails to find right away instead. Plus there were some really cool parts like the clock level where jumping in at specific times on the clock affected the speed things moved in the level, making some stars harder or easier, and the level which let you transition from big to small versions of it. There was a hell of a lot of variety in that game too.

So for me, I've been left feeling like the 3D Mario games got it right the first time as far as what I wanted, and since then they've just been gradually spiraling into a more linear version I have no real interest in anymore. The only fairly linear Mario I actually like is the original Super Mario Bros. but I think that's because it not only nailed the movement mechanics perfectly, but it could be quite challenging. I don't really even get that from the newer 3D games which are too easy, and sometimes a pain to control with the changing perspectives.