When the Desert Borderland first came it addressed some of the wvw issues but also added some of its own.
The main issue is scale. For a map that serves a player vs player game mode, lengthy periods of time travelling cross map is tedious and repetitive. So to address this, increasing the player count or scaling down the zones that interconnect main objectives would ease this strain (preference on increasing player count). It's almost more competitive to give the defending borderlands players a higher player count than their attackers as a sort of home advantage buff. In this way, defending multiple objectives increases in feasibility. In the current state, stalemate is broken because one side is left to reek havoc on one side while the other occupies the defending server. That isn't rewarding gameplay for attackers and is honestly punishment for good defenders. By increasing the defender player count this would push a welcome (subjective) narrative of attackers loosely joining forces or attacking multiple objectives simultaneously to break through the defenders defense while still be challenged at every step.
What I do like about the Desert Borderland is the aesthetic. The current borderlands (eternal included) could really use an aesthetic update too. This update could introduce a change where each third could tell its own story through its own distinct aesthetic that goes beyond red, blue or green. A server wide vote for residents prior to matching would be used to determine which third/color the winning and second place server will pick. What about relinks? End relinks.
Just consolidate the remaining servers. The chaos that is relinks must be done with. I agree that relinks solved the issue of stacked servers like blackgate jade quarry and to a lesser extent Tarnished coast and continues to break up power servers. However, it also fractures communities. The best way to continue to do one and solve the latter is to give control to the players.
Guilds already have player limits. To stay competitive, guilds have to constantly update rosters to make room for more active players. Compound this behavior with multiple guilds joining together to make a.... "Legion" and these two issues will be rectified. You know what else gets rectified, spies. Get caught siege griefing, flipping tactivators, and you'll be released from the "Legion". Inactive for long periods. Released. There would be enough turnover to keep communities fresh with new players and returning veterans.
Increase player count accross the board on redbl. With more players overall for the defenders of redbl. Or decrease the map size
Update the other borderlands aesthetically giving each third/color more diversity and character while retaining the geography.
End relinks. Consolidate servers. Give the WvW population control to the players. With turnaround guided by inactivity and griefing.