You know...I've been playing Rock in Modern, practically the same core, but I run x3 Grisly Salvage. This card is insane, and in a build that is missing Confidant I'd be interested to see what happens when you run it over the nearly strictly-worse-than-Bob Arena (yes they're different, "nearly", etc). Salvage does a few things and has high synergy especially for your list:
Face value: Fetch a needed creature or land.
Synergy:
1) Overload the graveyard with lands or card types for a swinging Goyf or KotR (the main benefit)
2) Combine with your Loam to quickly find either Loam or utility lands to loam back
3) Find targets quickly for your Volrath's Stronghold
4) Almost instantly hit Threshold to kick off Cabal Pit
It will dredge over Planeswalkers and other nonland/creature cards, but you still get some good use out of those cards with Goyf. If you chuck a
Raven's Crime into there somewhere (sideboard?) then you can quickly establish the Loam-Crime discard engine.
If you bring Lingering Souls mainboard, then you get even more value out of Grisly Salvage since at x3-4 you almost certainly will 'dredge' one over, so you can get a creature and a few tokens.
Unfortunately it makes the deck more vulnerable to total-exile graveyard hate (RiP...though quickly refills the yard after removing the threat) but I think the overall benefit would be very intriguing. I haven't tested it myself yet in Legacy since I'm very happy with the base list in the limited time I've been playing it and haven't time or want to retool the deck, but the synergy I see with the Modern deck is very interesting.