Some stuff for next season Frostmourne
-Naxx season should not be 3 months, 2 months maybe.
-Ulduar a bit longer like 3.5. Some fights buffed even further (hodir, freya, vezax hardmodes, for hodir just few more mils of hp on boss).
-Toc shorter than 3 months, prevent BV tanking anub hc somehow, makes the fight as easy as it is on normal.
-For ICC split the ID between normal and heroic modes so people can't boost themselves heroic gear while not being able to clear some "gatekeeper" bosses, buff should come slower and never reach 10%+, being in mega gear after a month is easy enough. And if the ID's would be split, people would gear up much faster too so the buff is not needed.
Could also consider shortening the overall length of Frostmourne cycle since PvP here is pointless and some raid seasons simply suck such as Naxx+ToC