This news is rather disappointing, but not perhaps too surprising. Some light trawling though the Tracker reveals that discussion and code patches around revamping the Forum have gone on since at least spring 09 -- that's 5 years. It's disappointing that this has not received a higher priority especially for a version that's slated for long term support. 6 months or so ago we were told that changes couldn't be made in 2.6 but to look for 2.7.
Is the policy to make version changes based on strict deadlines working well? I wonder whether it might be worthwhile to evaluate this policy in some way to get assessments from managers of moodle sites large and small. It's very disappointing when good solutions are implemented but in versions which managers cannot implement until the next academic year. For example, the fix to control sending feedback on assignment submissions which got 90 votes in the Tracker (MDL 33600) came too late for 2.6 and so was placed in 2.7 -- fortunately it is being backported into v2.6 (MDL-43985 -- which took 77 votes). In both of these Tracker conversations there are references to institutions having to upgrade to a version one point less than the newly released one -- thus 2.6 in summer 2014 rather than 2.7.
On another tack, though related, there seems to have been little progress on implementing Wiki and Survey upgrades. Both of these have high interest levels in the Tracker but there seems no mechanism to vote on priorities for the next release and so both of these are left on the shelf. It seems to me that a new version or point update that rolls out a major feature upgrade might allow a sharper focus on improving these basic features of Moodle.
Just some thoughts.