An idea I had about WvW is to actually change up the game play month after month. More than just tiers of servers shifting, but actually changing the way the WvW is played. For example, for one month boost all supplies and supplies carried by 50% (and see what happens). And then next month, supplies drop to normal, but siege weapons now do an extra 100% damage to players (and then see what happens). And the next month, siege weapons drop to normal, but say all keep and outpost gates are strengthened by an extra 50% (and then see what happens). Or even for a month, the “extra camps” like Ogres and Harpies and Krait and Hylek spawn twice as many “helpers” or the “wild beasts” on the maps ‘stampede’ (sort of an NPC zerg).
The point that I am suggesting is to keep WvW changing (different types of environmental rules) to keep it interesting and never the same.