Royal has never been a "party" line though. I mean sure, there has been the exceptional Teen Host here and there, but there has never been an environment that could rival Carnival. I mean, I know Carnival did not care in the least if there was grinding going on; I recall on more than one occasion even grinding with more than one person at the same time.
There is truth to what Ryan is saying about Royal though; it is really hit or miss with the teen program. You might get an amazing director (my first cruise as a teen was like that - ironically it was also on Navigator OTS), or you could end up with someone who desperately needs to get out more often. Hit or miss. On the other hand, I've not had a bad experience on Carnival mainly because we were all willing to "create" our own activities if we were dissatisfied with the official ones. I mean, we've done toga parties, played legitimate poker, thrown room parties, gone swimming, pizza night, dinner on the lido; you just need a group of people willing to have fun and a little crazy imagination.
The Royal program, while good intentioned, is not making any friends with the curfew either. I mean yes, its for the "general warefare and comfort" of the other passengers, but it kind of pushes potential teen cruisers away who do enjoy late nights and early mornings.