Roadmap, Plan, Purpose (of Engine Re-Write) in 2.60

This is primarily a Saffith question, so...

@Saffith

I'm curious, what your roadmap, and plan is, with regards to the 2.60 re-write. What do you plan to change/optimise, and what is the extent of the re-write? Just how much is changing, and what you you hoping to address?

I ask this, primarily for two reasons:

(1) Targeting suggestions, to the right place. If something is clearly outside the scope of 2.60, it'd be good to know that.
(2) Giving useful assistance. If there's something you are doing with 2.60, where assistance from other people may prove beneficial, jnowing what the plan is, would make that kind of help more practical.

There;s no rush on any of this, but when you have the time, it would be a nice thing to document the 2.60 roadmap.