The core can be a fairly vital component depending on what you need to accomplish with DNN.  In both my personal work and my employment work we stick pretty much to just using the installs.  However there are occasions when the core is needed.  This bug has been fixed in recent upgrades, but there was a problem with the Text/HTML editor removing the / characters in links.  There was a quick fix in modifying the javascript for the module to remove the problem but the better and more permanent fix would have been to modify the source, recompile and replace the dll's.  Luckily one of the upgrades fixed the problem but it was nice to have the source so we could fix the problem by recompiling.  The bug, for work, was a real problem as many of the users are not coders and didn't really know how to fix the problems and it was a lot of work for the two coders that support DNN to go and fix all of the new links.  For my personal stuff, I didn't fix the problem because I knew what it was and could fix it quickly.  Without the source being available the quick fix would have been okay but in the long run, wouldn't have been supportable if the fix hadn't been done in an upgrade.  Also, if the source isn't current and up-to-date then recompiling and getting the new dll's to work may become impossible. 

I do know it is a lot of work and all of the contributors to DNN have done a great job, so thank you for a great product. 

Any chance of getting the WebControls project updated to match with the current release?

If not, maybe someone can at least do it with the next release.