While I may agree reborn may be stronger, I'm not so sure it's as obvious as that.
The only string which actually truly benefits from having far TP cancel to make it safe on block is F4,2. Everything else that's relevant is hit conformable without the TP cancel options. B1,4 is hit confirmable to either 3, which is safe, or TP for a combo. 2,1 is +2 and is hit confirmable on its own, to either TP or just stagger pressure. B2 is the one move I can't say for sure... Is it reliably conformable between TP cancel and enhance? I'd say it isn't, but I haven't properly tested it, so I can't say for sure.
On the other hand, SR gets considerably more damage, both with the buff and with F3,2 and 2,1,2+4 strings in combos, and a couple fringe uses for DF2, either as an anti-air against characters with godly jump in which you can't contest with scorpion's normals cough Baraka, Shao, Geras cough or as a chip out tool. If you play a footsies based scorpion without relying too much on F4,2 I'd say SR might be the way to go, simply because the extra damage and tools may very well pay off.
I only started picking up scorpion a few weeks ago, and I've been running SR simply because I don't appreciate the defense meter drain from TP cancels, and honestly I only really feel I could really use the TP cancel for the F4,2 confirms (hence why I really really wish F4,2,3 was safe xD).