Small pvp server nitpicks that are not the highest priority compared to pvp class balance,etc but still worth mentioning. I am Alliance biased since I played it on Telabim, so maybe Horde has similar suggestions.
1) Stormwind is too easy to invade. Orgrimmar only has like 2 entrances. Meanwhile Stormwind has the front entrance, stormwind vaults, the tram, harbor, and from northwind, etc. Examples of ways to fix this are adding more guards around stormwind, making stormwind vaults default entrance the outside one because its a joke you can just walk right into the middle of the city, adding easier ways to get into Orgrimmar to balance it out, etc.
2) Horde can go a really long time without leveling in a contested zone. They can level without pvp flag in the barrens, then go to scarlet monetary or razorfen. Compared to the Alliance being flagged in Redridge, Duskwood, and wetlands. I think making the Southern Barrens a "contested" zone where Horde are flagged would be interesting.
3) Some neutral towns like Nordanaar have trash guards that should be fixed/reworked in some way to not be so easy to abuse/bug out.
4) Towns that have no guards like Morgan's Vigil.