A few questions:
1) Were all weapons that defaulted to 2 handed when drawn intended to be two handed only or were/are there some that might default to 2 handed but are intended to also be ep wielded?
Hard to say without seeing them all. But probably so, yes.
2) May I assume if there is a weapon that now becomes 2 hand only but is described in such a way that it could/should be one handed it can be flagged for review via bug?
Yep! If you see something that seems wrong, feel free to bug it/request about it.
3) Will half-giants/any other crazy strong race be exempted from this? It stands to reason that what would be a 2 handed maul for Joe the Human might be a 1 handed maul for a halfgiant.
Not currently. It's a binary sort of flag situation, meaning if the flag is there, it's 2-h only, and doesn't (currently) differentiate between hg or not. Half-giants do have their own 'version' of some weapons and they're bigger and do more damage. I'll look into this a bit more.