So from 6.5 to 10.5 damage, for a -2 to hit. Looks exactly like Power Attack, only you're not able to switch it off and spend another feat. How about simply skipping this in favor of something worthwhile?
Hmm. I checked over those Devotion feats; you're right, they're good stuff. I noticed from SS, though, that he qualifies for Thick Skinned, and can take it twice. That would be a total of DR 13/adamantine for him, rather than 9. How do you think that compares with the benefits of those devotion feats?
I would not go with the first level option because the character uses deadly concussion, which requires him to use a bludgeoning weapon.
For the 8th level substitute, this is a 7th level character. Although I've looked around a bit, and realized that it may be a good idea to pick up Combat Stability at 8th level, so that he can make better use of Combat Vigor at level 9. Fast healing 4 for 13 rounds at the start of combat on a character with DR 9/ada is pretty nice, I think. Between that and his martial spirit stance, I don't think he'll need to worry about his hp for a long time.
Earth Devotion looks very justifiable for this character; the ability to charge over difficult terrain would be fun. Law Devotion might also be nice, but I think he might be okay with ac 32 at this level. Heck, the requirements to hit him at all are rather stringent at this point. For 50% or better, he needs to be up against something that can accomplish a reliable +22 attack... which I believe is not especially common at CR 7-11. Am I wrong?
Oh, since a swim mod of -30 is pretty ghastly, I'm considering giving the dwarf Shape Soulmeld (Cerulean Sandals). Any thoughts on this?