With increase in population comes increase in...well...many things, some of those things are of a rather undesirable nature. To cope with that i suggest to increase the ignore list limit to about 200.
Also while at that, an "ignore" and "report" option added to "whisper, invite, target, cancel" in chat r click menu.
I do not know if it can be done. If it is client side, server side...i have no idea about such things.
It should not cause the "non blizz like" end of the world as it does not impact the game in any general way.
Yes i know there are addons out there which try to do this but the ones i tired did not work as hoped for.