The basic structure of Ashran is that there is one "road" connecting two bases. To get to the enemy commander you have to push your way up the road, capturing each node in sequence. Then there are 5 "off-road" events that take place in the other parts of the map. The main Ashran quest requires to win 4 events and kill the enemy commander once.
So the basic cycle of play is to skirmish at the current border in the road until an event pops, then both sides rush off to the event and contest it. Eventually one faction will win four events. That faction then makes a concerted push to get to and kill the enemy commander.
By and large, it's pretty fun. The different events give a feel of having several different battles within the larger battle. There's also mechanics like giving each class a new Ashran-only ability. The paladin ability allows you to judge people and send them to a jail in your base, which is greatly amusing. There's also items you can turn in to summon NPCs to aid your side.
There's really only two problems with Ashran. First, it desperately needs a catchup mechanic. If the other team is more organized or stronger, the weaker team simply loses event after event. As well, part of your honor gain comes from artifact fragments that you loot and turn in. But if you die, you lose half the fragments you've collected. And the weaker team dies a lot more.
My fix would be to give the side that loses an event a stacking buff that boosts them by 10% or so. If they win an event, their buff count drops by one. That should be enough to even out the sides.
The second problem with Ashran is that there is no point in defending your leader. If the other side is making a concerted push to kill the leader, the best thing to do is get out of their way and get a jump on the next event.
This problem is probably much harder to solve. I think any attempt at a real solution would just see the two sides explicitly collude and take turns killing the other leader.
It's ironic, but very often the best strategy in long-running PvP games is cooperation between the two enemy sides to maximize resource gain.