The republican healthcare bill is nothing more than a tax cut for the rich masquerading as a healthcare bill. By allowing insurance companies to increase rates by a multiple of 5 for those over 50 and denying coverage for those w prexisting conditions they ignore the basic concept of insurance which is to spread risk over as large a pool as possible. The end result will be increased cost and reduced availability of coverage for those over 50 but too young for MediCare. 
Additionally, they include multiple provisions not appropriate for a bill being processed under reconciliation ensuring court challenges if their bill passes. 
They're hoping the public will be distracted by midnight tweets and the circus in DC as they destroy American healthcare!