The fact of the matter here is that you don't know what's going to be proposed and to frame what you don't know as "an awful lot like the ACA" is speculative horseshit.
How about we wait and see?
It's not speculative horseshit, it's basic logic:
If you want a market based system that bans underwriting for pre-existing conditions then you need a mandate to ensure that people don't only sign up when sick. If you have a mandate that means some people can't afford it so you need subsidies. That's the basic three legged stool of the ACA and any market based solution is going to look a lot like it.
Not sure why conservatives are having such trouble understanding this other than the fact that it's embarrassing to realize that your health plan will have to be similar to the thing you had convinced yourself was evil.
Of course if you want to ditch coverage for people with pre-existing conditions you can totally change things. That's not what conservatives promised though. They said they had a mysterious better way for similar coverage at better cost in the works that they have just never found time to reveal in the last half decade or so.