Ragna has a pretty fair mixup game, as far as Blazblue's mixups go... Unless you're Zakiyama, who IBs everything, you're pretty vulnerable at the hands of a decent Ragna.
...Just try not to get cornered... IB and try to punish with his kick DD, I guess. I have trouble getting out of pressure with Hazama.
btw, I play against Tager, mostly, since my friend things Gadget Finger is the best thing to happen. Ever. So my Ragna experience is very limited. I also suck, so yeah.