I have no problem with a better bill. In fact I am very much in favor of changes. I just don't want to repeal the current bill before going there. If the current legislation is reversed I firmly believe it will be decades before we reform the system.
At the (big) risk of mis-stating your position, I think the internal reasoning might go:
"I think the present bill has important faults. But, I don't think we have the national consensus or the political will/courage to do anything better right now. We just had a bruising, damaging political brawl over this, and we are bitterly divided and 'fought out.' The new law has flaws that will become evident and we can fix these individual problems as they present themselves--they will be smaller, more evident, and more manageable to resolve than trying to re-think everything. We can incrementally improve until what we end up with reflects what the people, through their representatives, want. If we repeal everything, we are back to the big untacklable questions and everything is in chaos for a few years or decades."
I can understand that this line of reasoning. I can even see a case where the present law eventually turns into something I'd much rather see: Costs get so high that employers make the rational decision to pay the fines and dump everyone into the exchanges--good. With everyone in the exchanges, we have the makings of a private market--good. Maybe that will make it easier to get costs under control, but only if the costs are not transferred to a different third party--the taxpayers. Medicare, Social Security, government spending in general: We don't have good record of controlling costs when we lump them together and "somebody else" ("the rich", the next generation, etc) will pay the bill. OTOH, we have an excellent record of controlling costs when individuals pay for what they use. We just have to get a balance--Granny can't pay for her liver transplant if she needs one.
If the GOP is smart, they'll build a marketable "replacement" bill to complement their "repeal" campaign. The present bill is not popular, but elements of it are. Basically, people like the idea of more benefits, but don't like to pay for them. Big surprise. If a GOP replacement bill can be constructed that gets us to a better place more quickly than the current path (including all the incremental fixes we already see are coming--make them from the start), then maybe they can sell this. Unfortunately, it's a complex problem and the voters don't do well with complex problems.
Time is not on the GOP's side. Once the subsidy flows begin, the "tyranny of the majority" aspect of democracy will effectively take over and we'll have a new, unsustainable entitlement forever. That, I think, is the main driver for rapid legislative repeal or a judicial overturn of this law. I agree with that objective both for the "political" reason and because I think we'll be in a better place faster if we build a better foundation from the start. But I could certainly be wrong.