I agree.
She has a lot of bugs that needs to be fixed.
I doubt she will be overpowered if her bugs are fixed.
Yes, she has gameplay affecting bugs, but not ones that makes her unplayable and extremely weak.
She still has clear weaknesses and counters. Spammers, snipers and range attacks are still her weaknesses.
Sure, her icicle has range as well, but it also has a cast time, travel time and low firerate. Her best range are still close to mid range, and even then has most heroes mobility, invulnerability, CC or other means to deal with Mei.
Also, Mei has the lowest average damage from all the DPS’ers AND tanks. Her denial attacks is to balance out her low damage output.
She also has high sustainability and slightly higher healthpool because she is a close range hero with no mobility.