DLC Achievements & DLC Required Playlists?

Me and my friends have been working on getting achievements across all the Halo games at the moment and one problem we have encountered is the DLC achievements in Halo games, Halo 4 being the problem at the moment. I have every achievement in Halo 4 bar the Castle Map Pack ones, and it got us thinking should DLC become required in certain playlists other than the DLC rotation, similarly to the system in Halo 3.

Now I wouldn’t want every playlist to be DLC required because that would be unfair on players who just want to spend money on the base game, but should 343 start introducing the DLC into specific playlists and leave behind a few for non DLC players.

My idea was to follow Halo 3’s lead and do something along the lines of no DLC required in Infinity Slayer, Multi Team, Team Objective and Rumble Pit (Plus Flood/Grifball etc) to give a variety of gametypes, and then the remaining playlists to be DLC required. This would add a huge amount of variety to playlists such as Big Team due to the vaste amount of large DLC maps. Does anyone have any other views on this topic, and do you think more people would buy DLC if it was enforced?

P.S. Where would any of you go currently for Castle DLC?