I'm guessing its due to the arma server and whatnot.
tbh should've just given them there own forum instead of mess up this counter-strike related forum. There's allot of communities which support more then 5 games and they have one forum for it all, and it looks a hella more appealing then the current ambrosia forum 
ambrosia.co.uk (yum custard)
Oh, and don't you think the "global unread posts" is going to be a big clogged? You want to give each game it's own dedicated forum so the users who are solely interested in minecraft don't have to see the CSGO boards and whatnot, yet you make a global unread posts where they WILL see the CSGO topics and posts. 
Well, about different forums, that would take a lot of time and resources. And what's more, users would need to register to each game's forum they like, making it impractical and pain in the ass. What we have done is something simpler, many features are shared among subforums and many others localized. A few examples are: signatures, personal texts, messages.
Localised: unread topics, themes, categories.
About what's more appealing, well, when we changed forum theme, owners, staff, trust me, it was so hard to get used to it (at least to me). And thats probably the same case. (im not saying im a fan of it).
Its a pretty good idea and I bet we wont be the only community having this feature.
The global unread is basically "All unread topics", but globalised (from all subforums). I find it hard switching from one subforum to another just to check unread topics, and others find it useless to have to read unread topics from other subforums.