From what I've read one of the larger issues with free and simply verified accounts appears to be that the time added to the account is simply refilled and not added onto what's there. I don't know if this has been covered before, as the above thread about P2P is very long and I've not had the free time to peruse it - but here's my simple thought on it.
Have it so you can 'bank' up to say, double of what's refilled. Nothing terribly amazing, but not so awful either.
Free account refills 7/week - account can hold up to 14 hrs. So if someone has an hour left over they then have 8 hours the next week, or for more casual players who don't play every week they get the benefit of playing for 14 hours.
Verified account refills 14/week - account would be able to hold up to 28 hrs. Same premise as before, greater benefits.
The only people it benefits are more casual players persay, who wouldn't really want to put down for a month's subscription since they wouldn't be able to play ~all the time~ anyways and feel they wouldn't get a good run for their money.