Also, as I mentioned, it also cancels the damage prevention of protection abilities. There's not a lot in the cardpool on it's own (although
Stormbreath Dragon feels like a needless kick in the teeth against white), but you should keep it in mind if you face (or use, yourself)
Guard Gomazoa and
Gods Willing.
A note on the archangel, keep in mind that
Rhox Faithmender doubles the lifegain, so you end up above your starting life total.
I think Quest is bad. The natural psychological tendency is to overvalue combo cards because the mind imagines best-case scenarios well but handles probabilities poorly. Against a good player and deck, (i.e. when it matters) Quest won't have a large or early enough impact, and forces the awkward decision between dropping a 1-mana creature on turn 1 (which is what you really want to do) and dropping Quest to try to get it to trigger faster. Keep in mind, on the turn you make that decision, you're only seeing 7 or 8 cards - and the dream scenario requires Quest, 5 goblins, and 3 lands, so in most scenarios (especially since cutting a land will leave you even less likely to have 3 lands in the opening hand) you're gambling in the dark by playing a turn 1 Quest and hoping to draw into a combo early, that may not materialize in time.
I'd probably go with
Skullcrack, but obviously you should test in empirically. It does 3 damage as a base, which is essentially the exact goal for RDW (turn 4 = 11 cards; if 7 are spells, 7*3 damage = 21). The time it does the minimum 3 damage, coincides with the time you need the least help (the opponent isn't gaining life), while the time it does the equivalent of more damage is the time you need the most help (the opponent is gaining lots of life).