Your not the only voice about site integration. I can see where it is useful and wanted by many but I have absolutely no need for site integration nor any plans in the future for such.
But what is driving us crazy is the hacks. For example the smileys. It is a pain to add everything everytime there is an incremental release, so therefore we skip releases or worse yet we start on one then there are multiple increments and we have to start all over again. So some sort of module system would be helpful. That way maybe some of the features we add would not have to be rewritten everytime there is a minor change to the main code for security, etc. We don't have html allowed so a fix for html and a couple of minor tweaks still mean that we have to rewrite many things.
I don't really have an answer on how it would work, but that would cut down on the work that we have to do. We have started hacking a version recently only to have another release before we get 1/2 finished. As a result we are still with 5.0.9 and now we are looking at 5.4.2 with 5.4.3 being about ready to be released.