You’re 100% right about the weapon sandbox. I understand the desire for classic weapons to return in some capacity, but lets be real. A solid sandbox, both in weapons and equipment is the best thing for Halo. A solid sandbox isn’t a large one, it’s one with well-defined niches, with little bloat, and lacking a jack-of-all-trades weapon. This isn’t an easy balance, and Halo hasn’t really succeeded too many times in this regard.
Halo’s sandbox has had significant bloat ever since Halo 2, especially with Dual Wielding in the mix. I actually think Halo 3 almost nailed it, AR starts are extremely fun because they give the other weapons in the sandbox room to breathe, as well as forcing players to move toward precision weapon spawns and making them move around maps instead of encouraging a campier playstyle. However, Dual Wielding, especially Halo 3’s implementation, kinda killed that part of the sandbox for me.
So far what we’ve seen from Halo infinite is incredibly promising. Weapons have solid niches, and instead of several precision weapons in the sandbox with a similar RoF/Cadence, we’re seeing some incredibly unique weapons with well-defined ranges and roles. Even where weapons share engagement ranges, each weapon features distinct functionalities and mechanics that differentiate them from one-another. The Bulldog, Sword, and Hammer all behave incredibly differently, even though they share similar engagement ranges. At first, I was pretty disappointed to see the Classic Shotgun be removed, only because it’s interruptible reload was something unique about the weapon. I’ve backtracked that disappointment though, because I see how 343 is differentiating these CQC weapons. The Hammer is incredibly close-range, but it’s AoE is cranked to the max, the Bulldog is a mid-range counter to both the sword and hammer, without outright deleting people in one shot, it’s TTK increases dramatically at range.
Even looking at the mid range weapons, the Commando, Battle Rifle, and Pulse Carbine each behave quite differently, even though they share similar engagement ranges. The Pulse Carbine edges out the AR in range, but it’s cadence is quite different to the AR, as well as being more dependent upon leading shots. It’s a unique weapon in the sandbox, as opposed to the Suppressor/Storm Rifle/AR/SMG of Halo 5. From the looks of it, the Commando is a low RoF ranged weapon that doesn’t feature precision damage (though that has yet to be fully confirmed, just my observations). It’s a counter to the BR, without being outright better than it. It behaves differently and has a different cadence, unlike the Light Rifle/DMR/BR/Carbine of Halo 5. See how that is becoming a trend in the sandbox? Each weapon is totally unique from weapons of similar ranges and tiers. I’m stoked.
Where I don’t quite agree with you is RvB. This is a much more subjective conversation, but I really believe that Red Vs Blue is a staple of the halo series. It’s simple and effective and conveying who is on your team, to a point where you could give your mother the controller and she’d understand to shoot the blue guys. Telling your mom to shoot the guys with the red outline is a little harder to explain. Part of what made Halo so successful has always been it’s accessibility and simplicity. There’s a reason so many of us started Halo when we were kids. Hell, I started playing Halo when I was six! I was terrible, could barely hold the controller, but I thought it was awesome! No one had to explain to me who was on my team, because Red Vs Blue is so straightforward.
Aside from simplicity, I just think identifying players is much easier with team colors as opposed to outlines. In a flash, if I know I’m on red team, I’m not likely to flick my teammate in SWAT when I get spooked. I realize that there will be friendly outlines as well, but it’s not entirely foolproof.
I’m not saying that Outlines is no good and the worst thing they’ve done to the game, they’ve officially killed Halo for the third time in a row, and I’m never going to be able to live again happily; there’s no reason to go on… That spot is reserved for the ammo counter bullets being replaced by numbers 
In all seriousness I hope there’s a toggle for team colors, that way players can be represented how they like, but the Halo boomers like me can still rely on our Reds and Blues. It’d be a nice thing to have, and from personal experience, I struggle to see outlines in certain lights. I’m glad we’ll be able to customize the color of the outline, but I’d still love to see colors be an option! Good Post, hope you fully read through mine lol