Hi, Dielan. I was sort of in the same boat as you, because I felt like I had to stop completely maining Siegfried when I got SCV. I devoted to training with aPat after Edge Master in Legendary Souls mode caused my final time to be about an hour. (In hindsight, picking such a difficult character at the same time I crawled out of "scrubdom" wasn't a really good idea, but hey, nine months later I got the Legendary Souls mode at ten minutes, so I guess it was worth it, hah.)
In addition to looking at the link that Wandrian posted (which, by the way, is very interesting and I wish it was a little more comprehensive), I would also suggest to go into training mode and just simply take a test run at any character you may be interested in. Picking a main is important, and it's good to pick one that agrees with your playstyle, but it doesn't hurt to experiment with it first hand. It's naturally better to just get a feel of every character and just see what sticks and what doesn't.