A lot of them are better about this than WSG to be fair. WSG, Eots, and Silvershard mines are probably the worst offenders as far as being big wizard wastelands.
I think it’s ideal that BGs would have both large open areas favoring certain classes, and smaller areas / spaces with more LoS obscuring terrain to favor others.
But part of the issue is also that melee classes don’t really benefit from a cramped space with pillars nearly as much as ranged classes benefit from an open field. Free casting at max range is a huge advantage, but classes are still designed to be able to get out meaningful damage while being trained.
Pillars help both sides stall out fights. A range class can benefit just as much by backing behind a pillar until they get healed up, which forces people to either overextend if they want to finish them, or just swap targets. It also really benefits classes with channeled damage like rapid fire or ray of frost.