Certain Affinity/343 just cannot make maps that are fun to drive vehicles on.
Look at this. Angled buildings that serve as ramps and tons of hills and sand dunes for vehicles to have fun with, but there's also enough cover and enclosed space to facilitate infantry combat and also give infantry the ability to move around relatively and set up attacks against the vehicles. This is a good map because it give players in vehicles plenty of space to drive around in however they want, giving them a number of approaches and options at any given moment but also giving infantry a pretty good chance to defend themselves and fight amongst themselves.
The same is true of many of Bungie's other BTB maps (see: Blood Gulch, Sidewinder/Avalanche, Relic, Containment, Standoff). Vehicles and infantry both get plenty of opportunities to move around to their full potential.
Then look at any map in the Castle pack, especially Outcast and Daybreak. They're just a bunch of preset paths for vehicles to drive through, nicely carved out with tire tracks and everything, basically saying "you have to go this way" surrounded by hills and cliffs only infantry can get to where they can rain down endless plasma pistol overcharges and plasma grenades to destroy any vehicles unlucky enough to pass by. There's no room for interesting vehicle maneuvers except for "go forward" and "go backwards." Trying to drive a Warthog on one of these maps is just a frustrating experience of traveling down a straight line trying to make the most of the tiny degree of freedom you're given.
The way CA talks about filing Daybreak's airspace with rocks and walls for Banshee pilots to avoid is a perfect example of their approach to making vehicle based maps: Rather then giving vehicles the freedom to move around an open space where they can attack and be attacked by infantry, vehicles are forced down narrow paths that keep them constantly in range of guys who spawn with some pretty effective anti-vehicle tools.
If you're in a vehicle on one of these maps you have few other options than heading straight into a heavily trafficked area where you're constantly threatened by plasma pistols and grenades. Instead of pulling off sweet jumps and trading machinegun fire across the map you're stuck in a deathtrap that can only head straight at dudes who got their anti-vehicle tools off spawn.