Raiden's big problem is that he's both unsafe AND lacks dirt. In most games, if a character's pretty unsafe, they have a lot of dirt. Think of Akuma, and how he usually has a ton of tools and nasty offense, but he's about as durable as wet tissue and if you make the wrong call once or twice as him you're dead. On the other hand, characters that don't have much dirt tend to be pretty safe. This would be like Ryu usually plays, where his game plan isn't very tricky, but he doesn't take many risks to implement it. Raiden currently has the worst side of both those trade offs. In Thunderwave, it seems like he's supposed to play kind of dirty with the teleport mix ups and superman cancels, but they're not really that dirty and most halfway decent players won't fall for them for long. And in Raijin, it seems like he's supposed to play straightforward and safe, but he's just not that safe on any of his effective stuff. To make either variation effective, Thunderwave's teleport needs to be a lot more dangerous in terms of frame data, and Raijin's space control needs to be a lot safer.
Of course, for me, I'd prefer them to also plan his variations out better. There's no reason for teleport to be a 2-slot move. It's not for any other characters who have a decent teleport. Drop it to one slot and give him something else useful in Thunderwave, and put Jo Push in Raijin for combos.