I agree, but on the other hand if people know it'll only ever be 16v16, they're more inclined to dismiss it out of hand because they're after bigger fights or the ability to impact more people with their high alt bomber or stealth play.
Wiley.
If you want to do those things, then the Melee arena is where you want to be. If you want an RPS, then make an arena and set it up. If you want quick start fights, then Melee ain't it. If you want to play where bases cannot be captured, then you do not want to play in the Melee arena.
In other words, if you have a specific thing you want to do and it is not being served in the Melee arena, for you, then make it happen.
We really need players to stop focusing on going where the numbers are and, instead, go where they will get the kind of game play they want. Those custom arenas can be pretty powerful, but it is up to the players to make them and feed them.