Well uhh okay I'll go through some of her basic weaknesses.
She has no range on most of her normals. 5B has about double the range of all her other normals. Very low damage off combos unless you use charge. Her normals get stuffed out a lot. Her specials get stuffed out a lot and are usually negative on block AND hit. Her DP trades with almost everything. It is also projectile based. Also no invincibility on the actual hit. (It traded with Jin's 6A before...) Very tough time getting charge vs top 3 and couple other matchups. Due to very low damage, she pretty much needs to land 2-3x more combos than the other person, unless you actually get time to charge.
There are probably a lot more bad things about her, that's not to say she has no strengths. But I mean even if you guys say you like to have handicaps, the way BBCS works makes things kind of ridiculous. But if you guys still want to main or second Tsubaki, more power to you guys!
For me, I like to troll myself, so I main Tsubaki. Even if I still get randomly scrubbed out from time to time haha.