are there in place to prevent a midair between a VFR and an IFR in E?
The same defences you have in your beloved Class G, EXCEPT.......You are being positively separated with other IFR.
If you hit a VFR who happens to be in IMC (as I know one pprune VFR regular who likes to boast that his home made panel is fine in IMC) then what can you do about a criminal and deliberate negligent act (VFR flying in IMC)?
Balloon, Class E at Avalon was implemented to appease and shut one particular person up.