The L55-L59 battleground range is (in)famous for two reasons: this is the first range where an expac's gear becomes available, and this is the first range where DKs appear.
I will not speak of BC clown gear, other than to say that Orcs certainly do look pretty in them.
While it may have taken several months, the flood of Monks and Pandaren leveling through Azeroth has died down. The general makeup of your average leveling BG has evened out to an even composition of various classes. (For the record, the Mistweaver and Windwalker Monks are far more popular than Brewmaster, with a slight nod to Windwalker at the moment in the 40s/50s BGs.)
That is, until the Great DK Invasion.
I can only imagine what it was like those first few months of Wrath when everybody and anybody created a DK. I remember the one time this past Winter when I was the only non-Monk on my side in a Warsong Gulch battleground, but the idea of having almost half of an Alterac Valley run composed of Death Knights terrifies me. It's bad enough when there are ten of them per side in AV, but more?
The consolation I can take in witnessing DKs swarming over everything is that not a lot of them know how to play their class. As a player who leveled a Warlock via BGs in Cata, I know firsthand how little fun it is when a group of DKs decide to play Death Grip Ping Pong with you. The fact that I've not been Death Gripped all over the place when even clothies know to target me mercilessly speaks volumes.
That influx of powerful but unskilled DKs has reinvigorated BGs a bit for me. The slog of trying to get to at least the first expac, coupled with a long losing streak, can wear a player down. It got so bad at one point in a WSG game that I ended up parking in the middle platform above their base and waited for the thing to end. The Horde team had us on farm, but instead of people simply running away and not respawning in the graveyard, we kept feeding the beast. I couldn't bring myself to drop group, because WSG had only 4 minutes left in the timer, but there was no way we could win. So I got up and got some coffee instead of stressing over this.
"Get their flag! Get their flag!" someone said over BG chat.
"I can't," I replied. "They've got a Monk, a Lock, and a Feral protecting it."
"Get it anyway!"
"I'm not going to add to their HKs."
But on the flip side, with the instability induced by BC gear and new Death Knights, the Alliance has finally started making inroads on Eye of the Storm and has been dominating Alterac Valley.* I've stealthed in Stonehearth Bunker several times now, watched the wave of Hordies go by, and leave SHB empty for me to recap. You'd think that after the first three or four times I wouldn't be able to get away with this, but it keeps happening in either SHB or Icewing Bunker.
I realize that this state of flux will subside by the time I reach the Wrath level. DKs will gain more skill or will drop out, leaving a leaner, meaner group to contend with. Still, I intend to enjoy this chaos while it lasts. Rogues thrive on chaos, you know.
*YBMV -- Your battlegroup may vary.