Konkordski,
I'm not convinced yet either - just keeping an open mind. But I'm fairly skeptical - especially since what use is getting 30 people out 4 seconds quicker if the narrower seat pitch has been used to pack in extra seats which you'll need those 4 seconds and more to empty!!!!
For example, a quick look at some seating plans reveals that Air Canada have 260 Y seats aft of the second set of doors on an A330 - while Air Transat have 290. Presumably, Air Transat would need to be able to evacuate people approximately 12% faster than Air Canada do in order to get everyone out in the same time. Just as well they've got those tight seat pitches!!!