Map Design

So anybody ever notice how about half of Halo 5’s arena maps are good while the other half kinda sucks. And yet Warzone maps are all high quality with the lowest being Darkstar, and that map is decent.
What makes Warzone maps objectively better than most Arena maps? Is it the formula of Warzone?
Is it the fact Arena is hard to balance? Maybe its the fact REQ money gives more incentive? The size? Im not sure, so im asking you. Waypoint and any devs. If youre reading this, help me find the answer.

I thought that this sort of thing was true of almost any FPS nowadays. The “signature gamemode” of the game (WZ, in this case) gets more attention to detail from the devs, and the maps are better as a result. Outside of that, anything else becomes secondary, and it doesn’t matter as much if a map is sub-par.

Granted, I’ve never developed a game, but this seems to be the case with Halo games that have been released in the last 7 or 8 years, be it Reach’s Invasion or H4’s Dominion, and if this is the case, it may even be so in Halo Wars 2’s Blitz.