@
rev0lver was the one who claimed Lex vs. BG was even. I have MU experience against @x5ivestar and can honestly say she doesn't get up for free.
Against Shazam I don't see why it would be in BGs favour. She can't keep him out effectively and his command grabs out range her b1 (he out-footsies her). Shazam does big damage going in and his oki-setups can stuff all her wakeups.
CW is definitely even. I have extensive MU experience against @
n-megabyte and he'd probably agree. BG can't zone CW and j2 is godlike in this MU (stuffs wakeups, jump ins etc.)
I think you just looked and saw supposed low tier characters going even and thought "downplaying". There aren't many (read any) MUs that BG dominates to the extent of a 7-3. In fact, she goes even against a lot of the cast.
As for cartwheel, you can option select back dash which will avoid the low and block the overhead and high. I don't know about fuzzying it though. There's like a 2 frame gap so it's possible I guess (EDIT: you're better off back dashing because it yields the same result [the high and overhead come out the same time] but you get a bigger chance to punish the low). Haven't tested if Bane can armour through although I don't think so.