So over the Christmas break I think I’ll seriously look into it. Is there an official ... EE 2 for CodeIgniter fans doc?
I am afraid not, not yet at any rate (Derek Allard promised to write something up!), but it really shouldn’t be needed, either, at least not for getting started. If it helps, just think of EE as another CI app (which brings its own version of CI for the time being). The reality is a little more complicated, but not all that much.
So if I commit to EE2, will I be limited?
Not really. EE is very extensible, what with modules, plugins, extensions (and now, accessories). This has always been the case of course, but now that EE uses CI for these addons things should be even easier for an experienced CI-developer.
You’ll probably still have projects where pure CI is the better choice (and why not), but if you need a robust, full-fledged CMS there’s no need to look further than to EE.
on a page managed by the CMS ... the customer might want some very specific tool ... can I get that code in there?
Certainly. See this thread for a little more info: http://ellislab.com/forums/viewthread/137557/
In any template you can always access the CI super object with $this->EE, e.g.
<?php $this->EE->load->library('simplepie'); ?>
Some documentation for EE for CI fans would be great. Will there be any such material?
Start with the EE dev docs, would be my suggestion for now…