It's unfortunate that we couldn't include RHEL 6.6 support for APM 10, but as you know often things planned on roadmap get shifted\moved due to other issues.
However if you are interested there is a way we can fast track TIM support for RHEL 6.6 i.e via field certification process.
If you have a test environment to deploy TIM and can assist with field certification then here is the process
-Open a support issue
-We can provide a internal workaround to get around with TIM installation failure issue on RHEL 6.6
-Once TIM is installed\configured run some tests w.r.t recording, monitoring transactions
-If no issues are found during this whole process then we can pass these results to our QA team and if agreed formally add support for RHEL 6.6
Will this help ?