Hilde being low tier is just popular opinion and opinions are like assholes - Everyone has one and they're mostly full of crap.
But no, Hilde has every tool needed to win, She has usable lows, Knockdowns, tech traps, some okizeme (but not the best oki), high damage combos off of usable moves, excellent meter gain, one of the highest damage aGI combo's in the game, she has tech crouchers galore and 66A+B will make people scared to throw out certain lows (since it will beat out the mid option if there is one), her CE is the nastiest i16 punisher out there and her guard breakers are quite decent . She however lacks mix-ups and many of her good moves have abusable gaps in them.
No mixups is why she is not in the A-Tier.