Apologies for the tardiness, but maybe I can be of service.
Shakunetsu translated into the SSB system strangely. It's basically like ST (in that there's no restriction on its use), but it's likely dealing more damage. Much like ST, the only thing holding it back is the input--except here, you have to turn around if you're not doing it from the air. Sometimes a faster input is just that.
Is it true that SSB has stricter priorities on projectile interaction? If Shakunetsu has different durability or hitboxes from a standard Hadouken, that'd be reason to consider one over another too.
At max range Hadoken deals more damage than Shaku. Shaku only does 1 percent at max range, Hadoken still deals full damage. So at max range Hadoken is probably better.
How do you input standing True Shoryuken?
I'd like to know as well if there's a way to do this instantly while standing. So no crouching, walking or dashing first. AFAIK this is impossible unless you buffer it out of a previous action.
I have a few questions myself:
1. How reliable is ledge trump bair for Ryu? Is it true or can they air dodge out? Either way it seems like a solid mixup to me if they aren't buffering ledge options as it kills fairly early.
2. I've noticed soft hit nair at higher percents starts popping the opponent up instead of just sliding them across stage. Is this also effected by rage? If Ryu has more rage, will it start popping them up earlier?
3. How safe is nair in general on block? Can they attack before you down tilt if they don't powershield?
4. How much advantage does focus attack on block grant if any? Would focus on block, dash forward, downtilt be a true blockstring if timed properly?
5. What purpose does Ryu's jab serve? It seems downtilt and up tilt are better in every way. I know jab 1 - SRK works but it also works with downtilt which is safer to throw out (as it chains into more downtilts) and also hit confirmable (with 2 downtilts).
6. How much shield damage does hard uptilt - TSRK do? I think it might a great setup versus even a slightly used shield as you can buffer the TSRK within the hard up tilt (option select), and then it will only come out if you actually land it.
7. Does hard regular (non-true) SRK have startup invincibility? Or only TSRK?