Is this feat worth taking at all? If so, what's the best weapon to use with it?
Am I crazy in thinking that the falchion would actually be a good weapon with this feat? Or would greatsword still out-rank it?
There is, however, the fun question for the paragon goliathlock whether you can go staff with staff fighting and manage to get both the bonus from GWP (using a two-handed weapons) and dual implement spellcaster (using one implement in each hand), for a damage bonus of con + weapon + weapon + 3 + Item bonus (staff of ruin, probably, maybe with bracers to up your eldritch strike if you haven't retrained it when you switched to staff)

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.