I know this thread is a dead, but I have something that I've been using lately while playing that I think really helps Ragna's mix-up.
I'm sure everyone is aware of the 2A > 5A (whiff) tick throw method, right? I don't know if other people have already tried to use this, but while applying 2A pressure, you can go into the 5A (whiff) AND at that point, do any of the following:
1.High: You can go into 6B or TK Gauntlet Hades in an attempt to hit with an overhead. The problem is you can get poked out or thrown out of the 6B, while the TK GH is punishable if blocked.
2.Low: You can go into 2B or 3C to catch them off guard with a quick low. 2B will low profile most moves, and if they mash most things, both 2B and 3C will counter-hit (with CH 3C being a cool starter).
3.Throw: Self explanatory.
4.Continued pressure: You can simply go back in 2A to catch mashing, and from there go into standard pressure or tick throwing.
Options 1, 2, and 3 can all be beat by mashing certain moves, and all four can be beaten by frame-1 invul reversals. I still feel like this helps make his mix-up just a little more ambiguous at certain points, and is a really viable idea, especially since most of us begin pressure with 2A.