In some ways you are right, and I don't think Halo 4's are TERRIBLE, it's just, instead of making new potentially awful maps, they should start using what is already tried and true.
I'm sure some of these things have to wait for next generation console/Halo but...
1. Interactive maps: more terminal trains, zanzibar gates, high ground gates etc.
2. Progressive maps: more unlock parts of a map to progress through, similar to the late invasion variants from Reach but actually have more variety to each map section as well as objective parts and loadouts for each unlock too. So much potential here that just never gets realised to a full fleshed out progressive maps and environments/vehicles. Perhaps a new gametype waiting to be created.
3. Interactive progressive maps: I'd like to see maps that have moving parts, light bridges, dominion style base upgrades etc all rolled into one gametype and map. Imagine forerunner machines where parts of a map have to swing or animate into place etc. This would create dynamic map objects moving continuously and also therefore create dynamic gameplay as well. Now combine progressive unlocks with interactive unlocks and you have a unique style of play for both slayer and objective types with great variation.
4. Simple ideas that utilise the above:
4a) In action loading dock with pelicans/sabres landing and taking off.
4b) Forerunner or precursor machinery with levels and sentinels constructing the map around you or in the ahead unlock section.
4c) Ships with interactive jettison of sections during multiplayer. Imagine getting your team to safety and holding the other team back while you jettison their section of a map.
4d) Barracks where AI/NPC can be introduced to multiplayer. D-Pad for basic orders.
4e) This would also lend itself to Forge being able to have animated or interacting objects. Far and away enabling forgers to expand their potential for maps and gametypes.
I think you get the idea, keep it simple or automated but more dynamic variables for map objects and gameplay so you can play 100's to 1,000's of times and get a new experience most games.