When I fly some of the carriers in Europe, and especially with LCC, there is NO WAY an evacuation could be done in 90 seconds. Not with the kind of people on some of the flights... They seem to have no clue what flight they are on, where their seat is, where they're going, where to stuff their luggage. Sorry, but I don't trust those kind of people to contribute to a quick and effective evacuation if the situation would occur.
As for the seat pitching becoming tighter; it doesn't really help with smooth evacuations either.