: Honestly, if I were in charge of sandbox design for Halo 4... I would have
: announced on April 1st, 2012 that the whining between the BR fans and the
: DMR fans had become intolerable, and thus both weapons have been removed
: from the sandbox.

: When meltdown on the forums starts to wane, I post an update saying
: "Fine, they're both in." And then I waver back and forth on that
: point until someone makes me reveal that the BR-55 now fires semi-auto
: while zoomed.

: Yes, I'm an asshole. Doctors say it's hereditary.

: "See this thing? It's like a nuclear flashlight."
: "A what?"
: "Point it at something and..."
: FWOOSH!
: "...it catches on fire."
: "Anything?"
: "Anything. See that grass over there?"
: FWOOSH!
: "See those cliffs over there?"
: FWOOSH!
: "That Ghost over there?"
: Fwoosh.... wah wah waa boom!
: "Catches on fire and then explodes."
: "...can you hold it down and sweep it across the landscape?"
: "Yeah, but it drains the batteries like you wouldn't believe."

: I still think that Forerunner weapons should aspire to District 9-levels of
: making you look at the gun in your hands in horror and whisper "What
: were they fighting with this thing?"

: How's this for a Forerunner sidearm: Remember the Siren's ability in
: Borderlands 2? She immobilizes an enemy and levitates them over the
: ground. Give me that ability in a weapon the size of a pistol, and it'll
: be the perfect open-ended tactical weapon. With this gun, I can rip a
: troublesome enemy out of cover and whale on him without danger of evasion
: or return fire, or I can leave him be and concentrate on other enemies.
: Halo could use that.

I think the problem has been, as 343 has articulated, that those weird weapons just don't get used. So they have the tension of making a weapon unique and alien and thus people won't pick it up and use it (at least in multiplayer, when they discussed this years ago I dunno if they were talking about campaign as well) or making it samey. The homing abilities of the Forerunner weapons I think worked pretty well in the game, although I miss the pocket shotgun aspect of the Boltshot (and the fact that its silhouette never read as a shotgun... thus it felt cool and Forerunnery that this little gun could do so much damage, but then there was the issue with spawning with a 1HK and the fact that multiplayer it felt "wrong".)

I do think that cutting down on the armories of the enemy teams and focusing on fewer and more varied weapons would be a solid option. Bringing back more emphasized secondary modes for the alien weapons would also help (like that "stasis prison" ability you mention, or super combine effects that reward accurate hits, or even having one weapon perform two different weapon roles when scoped or unscoped (turning a shotgun-like blast into a laser-accurate semi-sniper or similar.) In multiplayer, just treat these weapons as lone power weapons rather than regular map pickups and you avoid a lot of the balancing issues.

As for the DMR/BR, I would have rather had the H2 E3 BR or the DMR (as I prefer the one-shot feeling, and 343 definitely made it feel far more powerful than the BR) but at least in Halo 5 and Warzone they'e succeeded in making the DMR feel much different and be clearly outclassed by the BR in certain situations, so they each have their niche.

Interestingly, I think the point you bring up about the Covenant not having direct human analogues in H1 is partially why I find its difficulty level on Legendary much better than any other game. You are weaker than the enemies, and they are far more numerous... but you are as capable, or far more capable of dealing damage. Single Elites are almost never a threat because you can just charge-stun them with a PR and whack them to death. The enemies don't have sniper rifles or ranged weapons so your pistol is even more godlike; likewise the massively powerful (even at medium range) shotgun. Only the fuel rod and the Wraith are weapons you cannot bring to bear on your enemies. It's a really interesting mix of power and vulnerability (with the health packs and three-hit melee) that just got wacky in later games.

Ironically the only other Halo game I enjoy on Legendary? ODST, which again dispensed with some of the sandbox analogs, treating Brute plasma rifles and Carbines as near-power weapons and making you a weaker character.