I remain unconvinced that segwit payment channels are necessary for an incremental improvement. You're welcome to believe in the God of Gaps, but code is written by people and unless you lock them in a hotel room and pay both the cleaning and writing bills (not to mention plumbing, electricity, faraday cage maintenance, etc), people write code slowly and generally pick the lowest-hanging fruit off the least-forbidding tree.

Why not just mine to a multisig of the smallest N miners, and leave them to coordinate between them how the payouts are distributed? This can start out as manual config mediated by a trusted Mth party, and evolve into all your payment channel voodoo wowee.