I think it would be really beneficial to toss more weapon unlocks into the mix. Keeping the same score boundary for the final loadout, but adding some more in-between ones.
It would also be nice if Sidearms only swapped with other sidearms (and the Bulldog at the end), while Rifles only swapped with Rifles.
I nice progression might be something like:
Disruptor - Sidekick - Mangler - Plasma Pistol - Bulldog on the Sidearm side.
Assault Rifle - Pulse Carbine - Commando - Stalker - Battle Rifle on the Rifle side.
This means there would be 8 level ups instead of 5. Meaning there will be a smoother transition of weapons.
I also would be open to having the BR and Bulldog be the loadout at 1850 like it is now, and pushing the Plasma Pistol and Stalker past that as rewards up to 2000. Since both a noob combo and the stalker are arguably better than the Bulldog or Commando, if a little bit less ‘comfortable’ to wield in a way that many players would rather not use them.
Also an alternate Power Weapon version of Last Spartan Standing would make for a really fun alternate mode. Where the weapons start at Needler / Hydra and escalate in power from there.