Turns out morph is still my favourite mechanic. I made the most ridiculous comeback at FNM against a R/B deck.
I've Aetherspouted away my opponent's Sarkhan Dragonspeaker and two Goblin tokens - she plays Outpost Siege, and next turn drops Stormbreath Dragon and brings me down to 5.
I currently control an unequipped Ghostfire Blade, Trail of Mystery, Mastery of the Unseen, Elvish Mystic, and Deathmist Raptor. I play a morph, leaving me with 1 card in hand (another Mastery of the Unseen).
Opponent exiles a land off Outpost Siege, and attacks with Stormbreath, bringing me down to 1. She then monstrouses Stormbreath to kill me. In response, I flip Rattleclaw Mystic and gain 3 life, surviving on 3.
I draw, and play another morph.
Opponent exiles Thunderbreak Regent off Outpost Siege, then casts Hero's Downfall at my morph. In response, I flip Kheru Spellsnatcher, gain 4 life (up to 7), and counter the Downfall. Opponent casts Thunderbreak, and in response I Downfall the Stormbreath (dat 3-for-1).
I draw, play a morph and another Mastery, and remember to equip it with Ghostfire Blade this time.
Opponent exiles a land off Outpost Siege, casts Dragonlord Kolaghan, and swings in for 10. I unmorph Icefeather Aven, take 3 to bounce Kolaghan, gain 10 from double Mastery trigger (now on 14), then block Thunderbreak with my 6/6 flier (Trail of Mystery + Ghostfire Blade).
Next turn, I manifest Whisperwood using Mastery, and just overwhelm my opponent with creatures and life.