The only solution? Excision before it metastazises and it's too late: Miners of the majority fork must band together and kill off the minority fork.
Seems like majority miners don't care enough to attack the fork chain. So much for that plan. Difficulty has adjusted quite a bit (although I'm not sure whether it's actually profitable to mine yet).
In any case, the bigger threat seems to be the Segwit2x fork. That's got a lot more backing from miners, companies, etc....