With respect to Smash, BlazBlue and most other fighters are very well balanced. Brawl's balance is so bad that we have it all the way to either G or H.
When you have smaller amounts of tier categories, that typically means that the balance is decent enough to where most, if not all of the characters are viable.
Here's a tier list for GGAC+ from a few years ago.
S: Eddie
A+: Testament, Jam, Slayer
A: Millia, May, Baiken
A-: Potemkin, Aba, Chipp, Sol, Venom, Robo-Ky, Order Sol
B+: Axl, Anji, Dizzy, Faust, Ky, I-No, Zappa, Bridget
B-: Johnny
Here, you're looking at what's considered to be the most balanced 2D fighter. You could say it's so balanced that two of the categories are made up of two sub-categories just to distinguish them.