I've battled every character on every bot difficulty, and with some friends who have varying degrees of proficiency in 2d fighters. Totem consistently presents a challenge for newer players with it's extended normal that can eat projectiles and double jump. The toughest problem when fighting TM is approach, Totem wants to lock you down and keep you out of reach, but if you're patient and block correctly you really don't have to worry about most of his kit. Every character is just as good as the others, you just have to find their strengths. I can't imagine how you couldn't find movement in any character other than the one with arguably the least movement potential.
Character selection so far isn't half bad. We've got most archetypes and playstyles represented, with some pretty unique combinations therein. I'd LOVE more characters (the dev is still working on the game, so we're bound to get at least one more) but I wouldn't say it's limited necessarily.