EASA is definitely the biggest cloud on the horizon, threatening to wipe out large chunks of the private IFR community. One pilot I know is selling his TB already and getting out of flying because he can't stand the thought of yet more paper collecting.
PRNAV (if it expands to enroute airspace) will kill off a lot of IFR GA due to the pointless and expensive upgrades.
Apart from the above, taxiing is the most dangerous part of flying, along with getting lost on taxiways
