There's more ways to add depth and sophistication that giving three of the captains new babies in short order.
Um, it was the DS9 "Final Chapter" arc, which aired in 1999, that established that Kassidy was pregnant, and Rebecca was born in
Unity, which was published in 2003.
Picard and Crusher finally got together in
Death in Winter, which was published in 2005; Beverly became pregnant in
Greater Than the Sum, which was published in 2008; and Rene was actually first seen as a character in his own right in
Paths of Disharmony, which was published in 2011.
Riker and Troi became a couple again in INS, which was released in 1998; married in 2002's NEM; decided to have a child in
Orion's Hounds, which was released in 2006; and Natasha was finally born in
Over A Torrent Sea, which was released in 2009.
Nothing's been "sudden" about these arcs.
I would have liked to see Picard & Beverly stay single or perhaps come up with some other sort of arraingement other than marriage. It's 300 years in the future. Imagine how different marriage today would appear to someone from 1712. Women not being taken as property. Gay marriage. Common law.
In the novelization of TMP Kirk talked about marriage contracts of a fixed length that were subject to renewal. Let's make the future different than today.
I think a future where the idea that men and women are equal is taken seriously and actually fulfilled, rather than just being given lip service like it is today, sounds different enough to satisfy me.