I remember Banner Wars, I played a few test games. It was okay, but I don’t think its return would be very beneficial. I see several issues with it coming back.
There is hardly any demand for it. This is the first time I’ve heard anything about Banner Wars in forever. No one really came to Havoc wanting a Bed Wars clone. It’s the same reason why gamemodes like Horizons and Map Maker failed, not because the gamemodes were bad, but because it didn’t fit the demographic of the playerbase. The server is known for their niche, open world, free for all gamemodes, and that’s what they do best. Thats why TMD has been so successful over the years, and to a lesser extent Hell Night and Mine Wars.
Not only would it have trouble among the server regulars themselves, it has to compete with other, bigger multi-network servers like Hypixel and Mineplex. A gamemode like Banner Wars would not hold up long against them. The only niche it could possibly fill is newer and less experienced MC players looking for a way to avoid tryhards on Hypixel, which would not be enough for it to be popular or profitable.
It would actually make more sense to re-release Hell Night. Skulls could be reworked to be more valuable than they were before.
However, at this point in time, any old gamemode has to be worth the servers time, and a gamemode like Banner Wars or Hell Night would have to wait before anything can be done with them. I can see Hell Night returning in maybe two years, if the playerbase gets bigger by then. Banner Wars could make a comeback if the server blew up and went mainstream, but that isn’t likely and even then, it will probably be completely forgotten by then.