... Windows really does run better if it's reinstalled at least every couple of years...
I have better luck with every 6 months :p
But back to the topic.
I like the local/public colors idea. This gives the user the ability to use up to 98 (I personally would like to see 0-255) colors, but, for clients that like to colorspam for god only knows what reason, its still only going to be in the 16 base colors.
Though, if these are added, dialogs will have to be redesigned to show the new colors. Adding in a simple 'More..' button would do the job. Pops up a larger display much like ctrl+k that shows all colors. (16x16 grid would be perfect for 256 colors..) Im sure an option to Enable/disable the extra colors would be needed to as there is prolly some users out there that dont want the extra colors.
If you take a look at irc servers.. how many of them follow the rfc standard anymore? Why should clients be forced to do the same? The server programs are trying to innovate.. I would think clients would do the same :p