Well, there are multiple problems some of which are easier to solve than others. An easy start is removing javelins from nord infantry, this will make all those one sided closed maps much less frustrating where nords simply chase down whatever the enemy team is.
Another easy fix is to implement the shield skill stat changes, which will make archer spam less of a problem. Right now if you're a Sarranid or Vaegir infantry pushing 2-3 rangers is almost certain death as even slightly different angles give them a shot over/around your shield since you have 2 shield skill.
This isn't a complete overhaul but does significantly improve the gameplay.
The circling is a harder problem that happens because players have no obvious goal beyond "kill" and winning/losing by objective is not satisfying either. Instant flags is better but usually we end up increasing the raise time which makes it pointless and people return to circling.
I would suggest something more like CS where you have objective and an attack/defend dynamic, but this isn't tested at all really and would need more work. Azan has suggested adding a gold-gaining feature when standing on flag which might be a more immediate way of getting people to focus on objective.
Blivandefar has suggested before set flag rotations e.g. instead of random/not previous flag, it always goes, if on Sandi: graveyard, middle, alley, repeat. You could then have this set as instant flag spawns, and if it's still ignored, add gold bonus. etc
You could even keep some maps as "free roam" style. Verloren for example I tend to find has much less circling due to the central tower mechanic so it could maybe remain unchanged, among a few other maps. Would allow for some difference in gameplay without it being a circle every round.
Just ideas.