It would be nice to have wiki pages with access specified by group as some information needs to be propagated specificaly to some group, like SW-Developers regardless of project.

ATM we need to create a project for this.
OTOH I don't see a reason why having it per group would be better except doing two less clicks. (Maybe someone else can)

So I guess this should rather be nice as having wiki pages split in section to which we can define different ACL.

This would be handy eg. in project Support, where I want to display different level of information to different user groups.