I'm pretty sure JacKaBo is aware of that interaction ;)

GY hate is really down to personal choice - I know a few players who swear by LotV and others who would rather have multiple one-shot effects like spellbomb/relic/surgical etc.... Take what you think works best for you but having some synergy (such as exiling your own griffins) is always a bonus!

Library really shines in drawn out matches as it accrues card advantage very quickly (ridiculously quickly if your life total is under no pressure) but, I nearly always find that i'd would rather have drawn a ponder instead - The deck in it's current form only really has bad matchups against faster combo decks and burn. Library helps none of these so I think it should stay in the board for now.

I would love a planeswalker to work in our deck but until they print one who's +1 ability is to search your/a deck for a creature and exile it I can't see us fitting one in. They might be nice in grindy games, but to regularly draw one you need at least 3 slots in the sideboard and, again, I think were better off trying to improve our combo match up.