I’d prefer reppa, too. If I remember, strong>fierce>fb/dp>SA1 dosen’t connect on all chars. You’d rather skip the fb/dp part. And yeah l.short2x>SA1 works. Unfortunately, those are the only ways for me to get reppa to hit anyone good. The initial range is just really bad - and punishing whiffs from chars like chunli is quote rare.
SA3 on the other hand, you could also link it from low strong and you can punish whiffs from 1/3 screen length. But everybody knows that.
The range on shinryuken is better than you might think, it still has a slight vacuum effect and the damage is pretty good so you could use it in anticipation of stray limbs(not ideal, I know, but that’s still one up on reppa) or on wakeup against low attacks. The very worst that could happen is you get the initial hit and nothing else. That’s not such a terrible proposition given your opponent is still on the ground, prone to Ken’s cross up game.
Also, practically eliminating the option of jumping as soon as you get that meter is a big plus in a game that is all about options. Against characters like Yun and Yang who depend heavily on jump-ins I think it’s pretty clear that shinryuken is the better choice.
Though its biggest fault remains the meter problems.