The main reason I’d upgraded was to get support for the wifi card in the ThinkPad, for which there were no drivers in the kernel used by 14.04. So I’m back to using an external USB wifi radio for now. I gather that the updated kernel, with support for my wifi, will be included in the 14.04.2 update coming later this month.
Reverting cost me an afternoon of work, mainly tweaking, but was well worth the trouble in this case. Sometimes the latest isn’t the greatest.