Every shield swipe gains you back about 10 tp. You are not--spamming-- shield sword in a raid, it only applies when you are tanking, and it is not a dps gain over RA (but is better than RoH, unless RoH is about to fall off as a debuff).

Shield Swipe is not a powerful TP recovery mechanic like I think you guys are looking for---it helps when you MT, but a Paladin that is on OT will run out of TP just as fast as you (and honestly, in a raid as an MT they wont be much slower.