Essentially, it works like multi-kicker
DeckedOutEDH released a video gushing over the cards power level, in both regular Commander and cEDH
There are convoluted infinites you can achieve with Medomai, but the card is ultimately pretty fair
Countermagic : Mystic Snake, Frilled Mystic, Draining Whelk Reanimation : Karmic Guide, Phyrexian Delver, Extraction Specialist Milling : Manic Scribe, Thieves' Guild Enforcer, Sage's Row Denizen Self-Milling : Stitcher's Supplier, Satyr Wayfinder, Balustrade Spy Discard : Burglar Rat, Mesmeric Fiend, Sin Collector Goading : Insufferable Balladeer, Jeering Homunculus, Vengeful Ancestor "Gain Control" effects : Hostage Taker, Agent of Treachery, Gonti, Lord of Luxury Clones : virtually all of them, though a few are decently pricey
That all changes now