I also think there is a decreased activity on the forum
I think the officers should spend a little time to respond to the forum

I think there is also a decrease in activity on bug reports
look at the number of members registered - on Dolphin 7.0.1 - only 59 members - http://demozzz.com/dolphin701b/index.php
I personally stop testing and bug reports - and weird stuff
often not considered because of bugs - or anything odd D7

This may explain the reduced activity

you do not use D6 - you see more surely not ever use D5
Yes little bug in D6 - but nothing serious - I have a site with 6000 profiles and D6 works very well - like a Swiss watch

for me at weak point on D6
lack of reactivity between members - I have not yet made the upgrade to D7 -
but I think with D7 and the new chat system and wall - this should improve the reactivity between members

on D7 is true that there are still bugs - but I think you can trust bonnex - to set the maximum Bugs
As you can see in : http://www.boonex.com/trac/dolphin/roadmap

the bonnex software - it's a dolphin
I see the evolution since the release of the version of D5 - there every time of great change -
boonex for me - it's a kangourou -