All I would say, is that when we first started crusing we felt that smaller might be better. And then we discovered that smaller means less choice, and actually, less intimate bars restaurants etc.
But, if you go on a larger ship, you get more bars and restaurants, and actually get a more intimate service as a result.
So yes, 2000 passengers sounds great, but if there are only 4 bars, they will be crowded.
Conversely, we were on Regal Princess (3000+pax) but so many bars that it was never crowded.
Consequently in Vines, the wine bar, after two nights, the waiters knew our names and also what our favourite wine was. Plus, lots of space, and not crowded.
Obviously your choice, but 7 or 14 days on a small ship is not always as good as it seems.
Having said that, the likes of the 5000+ ships are a no go for me.
Book Regal Princess in November - you will not be disappointed.