You honestly think these miners would do this [endorse Classic]... if they were happy about the roadmap?
Most are just frustrated at the infighting , politics, bikeshedding , and lack of consensus. I seriously doubt it has anything to do with the roadmap. They want an increase like everyone else.
Some elements of segwit are likely to be introduced if their benefits outweigh the costs of complexity, and with the clarity/cleaness of a hard fork, the market will control the introduction and timing of such a solution.
If you have evidence that those miners oppose segwit and simply want BIP102 without segwit than please let me know. Otherwise there is essentially is no difference in capacity between classic and core. Under certain circumstances Classic will have a slight amount of higher capacity , under others Core +segwit will have more capacity.
There are reasons where I can criticize segwit with , but am waiting to hear them from you to see if you understand segwit properly(and I believe the upsides outweigh the downsides)