There are only two changes I would make to the activity meters for Zeal contribution: Count damage dealt, not just kills. Count time spent capturing zones if the zone gets captured, not just actual captures.
It's fairly difficult for an individual to secure kills or secure capturing points and you might lose out on Zeal despite doing everything right to help your team.
The majority of players are going to be running around killing each other, and it is always a good thing for your team to be doing that, even if you aren't able to get kills, oftentimes players are teaming up together to kill opponents, so it's only fair if kill and capture contribution is rewarded, not just confirmed kills.
Other than that, we could bring back some level of monetary gain in Soul Wars by having a higher tier Elite Spoils of War locked behind owning a Soul Wars cape, or having 250 quest points, or similar.
Soul Wars could also take inspiration from Castle Wars Plaudits and have a similar "main world only" currency that makes it more optimal to play on the main world than to boost off-world or dolo.
Actually, I think there is a golden opportunity here. Jagex tends to seem to be alright with locking good money makers behind Quests. And that also seems to be their go-to preference as a way to reduce the amount of bots getting into an activity.
Hello???? Remember Nomad's Requiem and that really cool Nomad boss fight?
Jagex could totally bring back that quest and boss fight, and make the quest reward be the ability to purchase "Elite Spoils of War" with Zeal.
Then Jagex could put whatever requirements they want onto the Quest that they think is appropriate for separating real players from bots, and buff the reward shop again.
I mean, Nomad's fight wasn't really that advanced compared to PvM we have in OSRS today, but I certainly would like to do the "No More Nomad... No More!" challenge again for nostalgia sake.
Also, it would be great if the waiting area UI were to display to us how many players are currently in a match, and how long until that match is over. The Castle Wars waiting areas do tell you how long until the current match is over. It really helps to not have to guess whether or not the minigame is just dead and empty or if there's actually 100 people inside the minigame currently.
See my other page about "Improvements for Multiple PvP Minigames".