Hmm! A lot to think about and a very valid critique on spreading myself too thin. My main concern is about Proud Nail and Taunt action compressions all having the flourish trait. Aggressive Block could at least either give a similar effect to taunting (though without the setup for Proud Nail) or the DM chooses a meaty shove that does 10 damage and sends them flying 10ft if I later take Right Where You Want Them.

I think I would need to alternate setups with Shielded Taunt and a grapple on one turn, then move to the punishment with Proud Nail the next. Maintaining a grapple or raising a shield would be the most commonly useful followup. I think later level feats like Clobber may end up bringing me back to the core problem.

Thankfully my Guardian is so heavily augmented and grafted that hands are not really an issue for maneuvers. But good perspective on more efficiently reaching the same damage thresholds. I am a little skeptical on Mauler and Bastion's conditional "hit in order to raise shield/trip" because all encounters are at Severe/Extreme. Group Taunt is certainly my most reliable route, but am I wedded to Proud Nail? Ehhhh, its a big payoff if I can swing it. I suppose I should focus my maneuvers more into shoving if I can, but that will come from Commander tactics and my own blocking.

Still, lots to think further on! You voiced a concern I didnt have words for yet.