It looks like a logical next step is to store the optimized and compiled code. And after that, you can perform more aggressive optimizations on frequently-accessed scripts.
yeah if the pages stored hashes of the script, it could be pre-executed before you even visit the page. or common libs like jquery could be pre-parsed into binary structs in RAM.
Is next step that Chrome accepts js in the form of precompiled binaries from websites? Sounds a bit futuristic, but compiling would be reduced to checking the security of the binary.