I think its safe to say 343 want to keep personal loadouts, I highly doubt they will return to halo 3’s style of everyone has the same weapon on spawn.
In which case I think they can easily come up with a compromise in halo 5.
The issue in Halo 4 with multi-player in my eyes was randomness, the gameplay was far to random for my liking with the introduction of ordnance in particular. Here is my suggestions as to how to make the game more balanced by simply making everything similar.
Firstly loadouts. All primary weapon options should be mid ranged weapons ONLY. No precision weapons especially the DMR. The options should be AR, Storm rifle, Suppressor, Any other mid range they make consider to include. The reasoning for this is simply to bring back the sense of everyone on the map starting on equal footing but without removing the option to start with your mid range weapon of choice. This will also help prevent people from simply picking off people from the back of the map with a DMR as much.
The BR will spawn on the map as it did in halo 3, enough for some of the team but not for the whole team. Of course you will have playlists that allow spawning with long range weapons. The DMR should be a less frequent spawn to the BR due to the fact it has less bullet spread, I don’t think it should be a power weapon as such but it should not be allowed to be picked up by every player. It simply crates long range slug fests and encourages camping.
No perks, they are irritating and simply ruin any balance. AA’s in my opinion should be pick ups but everyone still would have sprint as a default. No plasma pistols/boltshots on spawn and no plasma grenades on spawn either.
Personal ordnance should be removed entirely and power weapon placements should return, ordnance created so much randomness on maps. It was all luck based and took away any concept of map control. The fact players could camp at the back of ragnarok with a DMR, pick off half the enemy team and then receive a sniper straight to their position is laughable. Placed weapons on a map will force players to actually move and rush for power weapons, the game will become so much less random as a result.
Remove forced flag carry and also remove the magnum while carrying the flag. I personally did not like this at all while playing CTF.
Bring back a skill based system IN GAME
Make it more of a challenge to reach the top rank simply by making game winning XP worth alot more than simply finishing it and create harsh penalties towards those who quit early.
Make vehicles worth using.
Can’t think of much more off the top of my head.
tl;dr - Mid range only for primaries, No personal ordnance, XP system based mainly off of wins, DMR/BR spawn on map, Plasma/boltshot spawn on map, No forced flag carrying, AA’s map pick ups, No perks, return power weapons on map.