On an individual job comparison of what their merits do for them, monk and puppetmaster are pretty much at the top for H2H's effect on their job.
Now if all you do is kill weak things on monk and endgame on PLD, you could make a case for sword/shield merits, but if you do equal shares of end game things, IMO H2H wins.
Shield skill definitely has use, but it really depends on what you're fighting on PLD for how much use, ie if you're often /nin you only really benefit from shield procs to save you from interrupting, and even then with reprisal you'll be blocking often when you might potentially get hit.
Sword merits can make more of a difference if you're low manning something where you're relying heavily on atonement for damage and hate, though I would much rather have 16 skill on a pure DD job than a tank.
OP already has sword merits, so you would have to consider how much fun/use it would be for you to wipe those merits and get H2H. It really depends on what job you play/enjoy more. Personally, PUP always takes priority for merits, augmented gear, etc so I'm probably biased.
80 Pup Brd, 75 War Rdm Drg Sam Mnk Pld Bst Thf Whm Nin Smn Blm Rng, 72 Drk, 63 Cor, 50 Blu, 40 Dnc Sch