From Avatar to The Soul Key is... what? A year? Very cluttered time frame.
The series should jump forward. It'll avoid the impression that these characters lives are nothing but one crisis after another after another after another after another.
That said, I'm not thrilled with the idea of DS9's pace being dictated by the pace of other series. If they keep making one DS9 for every five or six TNG/Titan books, DS9 will fall behind again, and have to jump forward again, leaving more storylines dangling.
I don't think it was anymore 'cluttered' than a season of the TV series.
As for 'one crisis after another' - its more like, one adventure/event after another, but thats exactly what Star Trek tends to be :P And imo, thats still not a very good reason to jump ahead - they could always write stories that didn't have huge galaxy-changing events or 'crisises'... It might not seem as drastic if they were just skipping ahead a year or two, but a lot can happen in 5 years!
And regarding your last point.. this can only lead me to conclude that we need MORE DS9!

In all seriousness, maybe it seems different looking back (as I wasn't buying Trek books when the first DS9 relaunch books started coming out, I have only been doing so for a few years now) - but it still seems to me that the majority of the relaunch weren't just one-off books... In fact... Avatar had two books, Mission Gamma was four, Worlds of DS9 was three, there was Rising Son and Unity in between - what we seem to be lacking atm is another duology or trilogy - Warpath, Fearful Symmetry and The Soul Key weren't a true trilogy... So I think the least the DS9 relaunch deserves before moving 5 years into the future is one last trilogy!