Well, Matt, you asked ....
As has already been suggested, more various regional sourcebooks, and the corp book.
I'd also like to see an expansion into space. I'm a MechWarrior fan, and I definately like the colonization idea get used more. From what I see, the technology for further space travel can be introduced, without even so much as a ding in the core system. The equivalent of a warp drive cannot be fitted onto anything short of a full sized spaceship.
Dropships can also be utilized/expanded on. Kintares IV anyone?
In my observations of A2089, I see definate similarities to the storyline of the Battletech universe, when the WarMek technology first came about, how it caught on, and how it evolved. When comparing to the BT storyline, we're in at the beginning of it all, unlike in BT where we get to start out a thousand years after this technology began to come about.
Unlke BT, A2089 has its initial warfare ON 'Terra' (Earth).
By adding the advanced colonization of other planets, we expand our warfare outward, with more battlefields than we can shake a stick at.
Different planets offer a whole plethora of different situations. Perhaps a desert planet, with extreme heat, where a Mek that worked well in Earth's desert climate, simply overheats alot without severe modification. Might our teams scientists have to come up with a new cooling system? New alloy for heat sinks? I bet that alloy would be moreso available on distant worlds.....
Corporations could easily fund a Merc group to assist with colonization. Other corporations could fund groups to STOP them.
I see an unlimited potential, for scenarios. And an ever expanding product line for Mongoose. Which is fine by me.