I would say the level design was as good as most halo games. It's nowhere near as poor as the general design of halo reach maps, some of which either had excessive space (, spire and the blood glitch remake to a lesser extent.) poorly designed for Balience (its been a while, but some of the accepted forge world maps, 2 of the starting forge world maps ) and one suffers from both. (Boneyard only uses half of the map, puts one team on horrid spawn. Easily the worst map in all halo games.)
Personally I like almost all the maps in 4 so far, vortex is poor, and there isn't enough small 4v4 maps in the vain of guardian/lockout but otherwise.