I'm on THM, and I am just eyeballing this but I see absolutely zero benefit to block rates by adding STR (ignoring the fact that it doesn't really help anything else on THM either). Granted, I can't add that much- 15 with the traits mages learn and a little bit on oddball gear- Only way I can add much more would be materia.

(I had set these traits in the futile hope that it would help basic and TP actions but it didn't do much of anything for those either)