The proposal maintains some of the stuff of Obamacare that's working well and that's popular: no more lifetime limits on medical claims, and people can remain on their parents' policies until they're 26. From there on it's a mix of old obsessions (tort reform, health saving accounts), deregulation, and ultimately less protection for the people Obamacare helps the most.
For example, they'll let insurance companies charge older people a lot more for premiums. Under current law, they can only charge older people three times as much for premiums than younger people; Republicans want them to be able to charge five times as much. States could change that rating, if they wanted, under the Republican senators' plan. The individual mandate is gone, as is the ban on insurers rejecting people because of pre-existing conditions. That's replaced by requiring insurers offer insurance to anyone who has maintained "continuous coverage." The proposal overview doesn't say how this would prevent people from buying junk insurance, then upgrading it when they got sick. As far as the people with pre-existing conditions, this plan would help states restore the high-risk pools some of them maintained to cover the sickest.
The Republicans would replace the subsidy lower-income Americans get with a less generous one. Now subsidies are available to people making up to 400 percent of the poverty limit, Republicans would replace it with a tax credit to people making up 300 percent of poverty, and require means testing for that help. The tax credits would be funded by capping the tax cut employers get for contributing to employees' health insurance (yes, a tax increase for business proposed by Republicans, believe it or not).
It would also end the Medicaid expansion and basically block grant it, giving states more "flexibility" to choose how to spend federal Medicaid dollars. What happens to the millions who've gained coverage through expanded Medicaid? The plan doesn't really spell it out, but if states choose not to provide it to people with higher incomes than they currently do, then those newly insured folks are out of luck.
Pretty much everybody would be, as the National Journal summarizes: the GOP plan is "for people to pay for more of their health care." But, hey, it's some progress. It's still pretty much crappy, but it acknowledges that Obamacare and its reforms changed the health care landscape.