Is it possible to time nair so you crossup shields? If so, maybe we could nair, land behind, ftilt. I'm in the lab as we speak, so I'll test this stuff.
Edit: yup, the nair thing works. Other possible shield breaks:
Strong jab ftilt
Weak dtilt
Ftilt to multihit fireball at close range puts them in a bad position. If they block the fireball their shield is broken, but so far as I can tell, the fireball covers rollback, jump, and spotdoge. If they figure this out the hard way and start rolling towards you, maybe throw out a dragon punch? Anyways, I'm gonna have to test this option out in real matches. It sounds great.
falling sweetspoted fair (on shield) to ftilt is a thing if you have superb timing. (I only did it once without getting shieldgrabbed)
I'll edit in anything else I come across.
Ok I did some testing.
Dtilt until out of range (depends on your starting range) followed by ftilt works. The enemy gets the opportunity to throw out any move that takes 5 frames or less. As long as they do not have a move with good range that starts this quickly the ftilt will connect. Essentially this limits the entire cast to only having tilts and jabs as their interuption option. Opponents that don't have a tilt with good range will take a hit. Currently tested on Sheik, it works, she can't throw anything out during that 12 frames to hurt Ryu as she's out of range, Ryu steps in and ftilt connects. Her options here are jump, shield or roll away.
My assumption is that this will work for most of the cast, I'm betting on weapon using characters having the range to interrupt it. I main Yoshi myself and I would GUESS that Yoshi's dtilt also has the range to interrupt it. It comes out in 3 frames and has fairly good range, but it might just barely miss.
Utilt>Ftilt also seems viable, but the range it puts opponents away from Ryu isn't as good as dtilt and enemies will likely do their interrupt with nair - There's a LOT of good nairs in the game that I think would connect using this method of shield breaking.
I wonder what else we can pull off... I can't test for quite a while now, but theorycrafting... I think
grab>pummelspam>groundedrelease>ftilt
I've been testing pummel spam with Ryu because I use it with Yoshi. If an enemy wobbles out of grab during the hit of a pummel animation it ALWAYS results in a guaranteed grounded release. With Yoshi I do this and follow it with jabs as a combo against much of the cast. What you have to bear in mind is that the grounded release for every character in the game is a slightly different distance though. The characters I've tested on so far aren't in jab range after the release, but they may be in range for more dtilts, OR you might be able to follow the release with a strong ftilt.
The pummel release needs testing for combo potential. It's the only way that Ryu's combo game might be extended from his grabs. Right now his throws (rightfully) don't give him any combos as they don't give any combos in Street Fighter either.