It's a shame they haven't brought Racoon Mario, Frog Mario or Cape Mario back they were awesome power ups. Frog Mario could swim so smoothly it was jaw dropping.
while the cape was cool, it was completly broken. I can't count the number of times I skipped entire stages with the thing. Same goes for the Racoon, but not quite as broken however it would have made getting star coins way too easy.
As for the frog suit, it got replaced by one of the best suits ever. The Penguin suit. It does everything. Shoot Ice, swim, slide on ice/water, walk on ice.
Anyways, I just competed the entire game, and you will probably get to the point of pulling your hair out on a few stages trying to get the star coins. However, it is quite rewarding to have 5 sparkling stars on my save file
I don't think the cape was broken by virtue of being too powerful (it certainly was much less useful than the P-Wing in SMB3); what was broken about the cape was that it was so damm easy to get one.
It's easy to get any power up in any mario game. Just go to the first stage that has it, beat the stage, use the powerup where you need it. It was broken because you could skip entire stages.