Overview
In a nutshell
Yoshi ranks 28th on the tier list due to his extremely 
learning curve due to extremely difficult advanced techniques, over-reliance on his double jump to recover, making Footstool Jumps, Meteor Smashes, or certain special grabs very dangerous to him (although he can air dodge during his second jump to gain invincibility), abysmal out of shield options with a poor roll dodge (although immunity to shield stabbing helps somewhat) and poor kill power without quick attack speed (except for down smash, which isn't a reliable killing move, neutral aerial, which needs to be hit within the initial frames and generally needs to be off-stage, and up aerial, which is a bit situational) resulting in below average and tournament results.