based on the profiler output you provided here are possible performance issues:
- session start takes too long. this has been covered here Long Running Admin Page Requests Blocking Other Requests. try switching session storage to database and see how it affects site speed.
- inspect header.phtml, top.phtml, 1column.phtml, place Varien_Profiler::start Varien_Profiler::stop here and there to identify the slowest part.
- check if you have mysql query cache enabled. by default modern mysql servers has it disabled. enable it.
- I see EAV_COLLECTION_LOAD_ENT called 16 times. it is called when for example you load product collection. what collections you are loading? do you really need to load it 16 times? try to inspect templates and lower than number.
