Raiden definitely has issues against the top tier hop pressure characters, but I think he's high tier anyway. Most the just-under-top-tiers have issues in those matchups. I think that 1) having anywhere juggle tools automatically puts you pretty high tier. Being able to convert off nearly anything is an incredible tool to have, and 2) having an overhead that can be canceled without HD is also extremely useful. Couple that with a 1f cmd grab, a great anti-air dp move, and insane damage output and that's a recipe for high tier character. He definitely has glaring weaknesses but the tools are all there.
As for Kula, I think she's underrated. I can't agree with people putting her at the bottom. Having a long range 4f normal that is special cancelable alone is amazing. She gets full punishes (that many characters can't even get) leading to safejumps pretty easily. Couple that with 2-hit throw normals that are cancelable (which lead to great corner damage for just 1 stock on hit), an amazingly fast/active/lengthy j.B, and amazing guard gauge depletion due to her weird stand A bug, she's solid mid to me. Her DP is okay too. She suffers from not having an overhead and ineffecient damage on her drive cancels but they all lead to easy safejumps in the corner which helps balance it out.
Leona is NOT bottom tier, surprised we're not past this assumption yet. Neither is Billy, especially after his b+A xx spinny staff free cancel tech, he gets great damage.
It's so hard to put people in bottom tier in this game, since the balance is good. Mai and Elisabeth are the two worst characters to me. Mai just has to work a lot harder than the rest, and elisabeth is just so damn stubby she has zero ground game aside from gimmicky slap spam. The fact that she almost has to take to the air to mount an offense really cripples her IMO.
Oh boy there's some nastiness going on in here. Ralf better than Kim? Dive bomber safe at all times? EXs that make up for his weaknesses? Yikes. Not gonna go into that, but no, no, no.