but a lot of mod packs are not, such as ftb monster, or attack of the b team, which are still in 1.6.4.
But also think about it because although I hope this is 1.6.4 for my mod pack the others you have mentioned there are stable for the most part and they are done with adding any new mods into the pack and will not do so. Even a couple you mentioned there are not even updating mods in the pack no more because they are focused on updating to 1.7.10 .
So I make a good point here. So with this still being 1.6.4 it is attracting the smaller audience that do know how to make mod packs and or add mods to packs there self , and that audience is very small . Although it is a pretty simple process of making a mod pack or adding mods to others ,a lot don't know how to do that .
If I personally had to set a standard, it would be the first version of every new major update. That way, mods are brought out quick and they are likely to work with the updates that come afterwards along with them never being to outdated for players to care to use them. That's just my opinion though.:D
luckily, this mod will be for 1.6.4 when it comes out, so that means i can still use it. plus, i'll also be able to play the aether 2 when it updates as well, those mods are one of the only reasons i'm choosing to not go past 1.6 yet.