Right now, I think Hydreigon and Thundurus are our best options - they give us offensive potential while keeping our team flexible in regards to weather / choiced mons etc. Also, regarding scarf Landorus - I initially considered him; and turns out U-turn cannot OHKO Celebi; and an unboosted Giga Drain takes away over half of Lando's health. Which, honestly, is a pain in the ass; because we require Celebi to have taken prior damage, or she will most likely proceed to heal up with +2 Giga Drains and Leftovers. Concerning Deoxys - it's a cool mon and all; but our opponent only has to pick a relatively fast Taunt-user and we're done for. For this reason, I would change Night Shade for Magic Coat. While having no attacking moves turns us into "taunt bait"; Magic Coat ensures that, with good prediction, our opponent's taunts will turn against them, giving us free turns to set up our hazards. EDIT @ below: Deoxys-D isn't going to be dishing out damage nor staying out for long due to lack of Recover. After he's set up his hazards, all he can do is take a hit or two and die; since he won't do anything else. Magic Coat at least lets us bounce status and such back - but that's just my opinion.