A few suggestions for improving the server in the context of BG.
1. Absence of some consumables on Blackrock - you can't buy or craft it at all.
For example, there's no elixir of camouflage on BR, it's impossible to get at all. This elixir may be very important in certain BGs and situations. Which gives an unfair advantage to players from other servers.
There's also no some other consumables, for example, Magic Dust (~10g on the IC), Blackened worg steak etc.
Please consider adding the above-mentioned consumables to the vendor.
2. Recently prices for Free Action Potion (FAP) and Living Action Potion (LAP) were set at 5000 honor per one, so even fully geared players can't use it quite often (compared to IC players) - you have to buy all the other potions and scrolls too.
On IC or Lordaeron these potions are dirt cheap (~60g for a FAP on IC for example). While I agree this is one of the most powerful potions in game, they're very cheap and affordable on IC and Lordaeron. Furthermore, usually IC players are better geared than BR players (in top GS BG bracket) and often play as premade vs random players. I have played a lot of BGs and I've never seen a Blackrock premade, but I've seen a lot of IC premades and even some from Lordaeron. In this way, the already non-dominant server is further and significantly weakened in top GS BG bracket.
I think it is necessary to consider the possibility of significantly reducing the price of above mentioned potions. Maybe not to100 honor if you want to make their use less frequent, but to, let's say, 500 or 1000.
3. Despite the fact that I have a significantly positive win rate, playing solo with merc mode on, I can't help but notice, that the Alliance wins much more BGs than the Horde. It doesn't show up in the stats, but I feel like the vast majority of the time (like 75% or more) I'm playing Horde. Considering the situation, it's not profitable to enable merc mode (or to play Horde) for an average player, who is not looking for a hardcore challenge.
A solution could be to introduce some bonuses for players who are on the Horde side and/or have the mercenary mode enabled. So, for example, you get more honor for win (and only for win, not for lose! - to prevent players from enabling merc mode and farming honor by losing) playing as Horde on a BG.
I believe the above suggested changes would make the players' position more equal and, in general, improve the balance in BGs.