Your right, he should try more. But seriously, their is no need for me to agure here. Mario lack's what crash does in first three games, the simple start and finsh style of the games, works well in such amazing wonder and style.
Each level feels like's its own, even if it's part of the same environment, mario hasn't done, When ever you did a level with a theme of another, they would always keep you on your toes, and push your abilty to control crash well enough to not die.
Crash is fun to move around and control, crash even has amazing water and ice levels, where the speed comes into play around smart traps, hazards and ememy's. Yes everyone hates the bridge levels, but no one ever calmed they were bad, they were just hard, and it took more than just simply moving forward to beat them.
The inculcation of the turtles was a perfect way to do this, because you had to take your time to make the right jump, and even if that was too hard for you,
the ropes on the side of bridge if you learn how to use it, you could cheese your way though the level's so easily.
Super mario bros 3, agured to be the best of mario games. Is still shit compared to crash, the gimmicks, if you could call them that, were very stale and boring, usually the level had a theme, unlike with crash, where a level was it's own theme and had it's place in the world as it should be.
And because crash is always in a 3d plane, even side scrolling levels are uniqe as you can use the 3d to your own abuse, whether to get around enemys or even to get secrets in the levels them selfs.
Crash is better. because ironically Crash is smarter.