Hi Nadine...and WELCOME!
You will find a number of former CC posters here...and, as you know, with good reason! And the ones you find here are international, younger and older, like the bigger ships or the smaller ones. In other words, there are more than two types of Seabourn cruisers.
Personally, as for children, I don't think those in their 20s or 30s are the same as the ones in their 10s or 15s. But what I do think is that I cruise with children (mine and others) all the time and am generally baffled by the over-the-top concern about the kids...when I have more issues with inappropriate adult behavior (though even that is quite limited on Seabourn).
My kids (15 and 11) have been on over 20 cruises and I just don't take them on Seabourn because it wouldn't be fun for them...personally. There are some young children that seem perfectly content. The style of Seabourn is different from Regent (they have been on it) and Crystal (larger ships and more activities) so they work/will work for my kids.
Since my first Seabourn cruise I have seen a few young adults and they have never been an issue of any sort. Some are a bit lively, but then again there are some older folks (including some CC'rs) that are even more lively...to be kind.
That said, I think Seabourn learned a bit from the former lower prices enticing families with younger children and has learned that for a number of reasons lower pricing doesn't mean higher profits through volume sales. So I do not think you will find nearly as many children on onboard in the summer anymore.
Sooooo, I guess the short answer is "Whatever floats your boat" when it comes to children generally and particular children specifically.
As for Seabourn policies that bother me? I really can't think of any off the top of my head. There are some minor variances between the larger and smaller ships from an operational standpoint that I wish could be more consistent, but other than that, in an imperfect world, nothing really stands out.
OK, I gave you may take, do you want to give yours????:-D