Out of all the classic card effects in Magic , lifegain might get the least respect
Izzet Metalcraft (2.6% of the Winner's Metagame) 4 Scalding Tarn 4 Urza's Saga 4 Emry, Lurker of the Loch 4 Tamiyo, Inquisitive Student 4 Mishra's Bauble 4 Mox Opal 4 Unholy Heat 4 Metallic Rebuke 4 Cori-Steel Cutter 3 Mox Amber 3 Quantum Riddler 2 Steam Vents 1 Island 1 Breeding Pool 1 Thundering Falls 1 Mountain 1 Otawara, Soaring City 1 Haywire Mite 1 Flame of Anor 1 Soul-Guide Lantern 1 Aether Spellbomb 1 Skateboard 1 Pithing Needle 1 Flooded Strand 1 Spirebluff Canal 1 Minamo, School at Water's Edge 1 Preordain 1 Fiery Islet 4 Consign to Memory 2 Blood Moon 2 Force of Negation 2 Fire Magic 1 Strix Serenade 1 Flame of Anor 1 Shadowspear 1 Vexing Bauble 1 Mystical Dispute Izzet Metalcraft relies on a large assortment of cheap artifacts to unlock the potential of Mox Opal
If it does trigger, it will check again when it tries to resolve
Overall, pretty cool
Keeping Kefka alive a whole turn cycle to use his ability again might be tough, but at least in black there's a fair few protection spells
Unlike some issues, where there is a pretty clear right or wrong answer, leaks firmly fall into a very gray area, in which how you personally interact with the game and how much disposable income you have to spend on the game likely play huge roles in where you stand on the issue
