I'm going to preface this with a blanket statement. :
The lack of options in Halo 4 is definitely a negative, I agree. I honestly think that if you expected to have the same number of options as in Reach, then you were seriously deluding yourself. Reach was made after years and years of working building and testing features. Bungie had a code base dating back to the 90's for them to build on and Halo 4 was a quickly slapped together team of professionals who had a handful of years to try to include as many features as they could.
Comparing the games on number of features is a bad idea because everyone knew that there was no way to include everything that everyone wanted.

: Perks belong in COD, not Halo.

Again, that is just your opinion. If you think it is that unbalanced then why is AGL using AA Ordinance in their "competitive" gametimes?

: running around in nigh-invulnerable Mantises or power weapons that
: seemingly never run out of ammo or guys who can spend more time cloaked
: than uncloaked or guys that know where you are at all times because you
: were the last guy to kill them.

This just . . . is a complete lie.
The ammo in Ordinance is very much limited. The Nemesis upgrades lasts for FOUR SECONDS. Not "at all times". And yes Mantises are powerful, but no where near nigh invincible.

: go as far to say that it's high time to go back to the classic Golden
: Tripod. Adding a fourth and now a fifth leg has done little if anything to
: improve Halo's core gameplay.
Ordinance are not a fifth leg, but yes REACH made a bad call when they added a 4th leg. Halo 4 is equal to Reach in that respect.

: structured to where you only have set weapon spawns at the beginning of
: the match — for example, there will always be a sword and incinerator at
: the bottom mid of Solace — but after that, it’s largely random. . .
: Whereas classic-style weapon spawns promoted cycling
: around the map and engaging in proper resource & map control so that
: one’s team can gain access to the best weapons...
: Fortunately, Certain Affinity made map
: ordnance have fixed, regular spawns, which gets rid of the random element.
: 343I should go do the same with all the maps they made.

Map ordinance is a little weird to be sure, but I wouldn't say it is necessarily broken. It is still an even playing field, it can't favor one team.

You act like "classic-style" weapon spawning is a thing of the past, but it isn't. There are gametypes right now in matchmaking where you can camp a weapon spawn all day if you want. It is little more than variety in the type of game you are playing. If you don't like it, play the other versions. Halo will always have gametypes in matchmaking that certain segments of the population can't stand, and others love.

: Also, the whole "rewards for good play" thing is bullshit too. It's
: like killstreaks in COD. It's bad enough that the other team is donging on
: you, but then the game rewards them by letting them summon bombing runs
: and attack helicopters. How is that fair?

Again very much an opinion. Notice how popular COD is. The competitive scene is getting huge and it still outplays Halo in online. People love killstreaks, both competitive and casual players.
Halo took a better route though, in my opinion. With killstreaks the better you do the more devastating killstreaks you get which, like you said, just makes it easier on the better players. Halo keeps it on an even random rotation. So the dominating team might not get dominating weapons.

To be clear: I'm not a big fan of the randomness either. I just don't think it breaks the game.

One of the biggest things I hate is getting 5th place in a match. Beating the crap out of your team, but still losing. This is a huge problem in random online matches. Every now and then an ordinance drop will turn those tides and not doom me to a loss simply because my team kind of sucks. 343 acknowledged that there is already randomness in Matchmaking. Randomness that they can't completely get rid of. So they tossed us something to help, occasionally rewarding your decent play with something that could turn the tide of a game, if you are good enough. If the other team is legitimately that much better than you, a rocket or two isn't going to change the whole game, but it gives the lonely player a way to save himself.

: Ergo, Reach was better in this
: regard. Bungie weren't the ones to deviate from the level playing field,
: so blaming them is a bit disingenuous if you ask me.

Adding Armor Abilities at all deviated from the level playing field. There is no doubting that. Those with sprint could always outrun you, only certain players having invis, jet pack letting players get a better angle than you. Again, Reach started on that path, Halo 4 just followed.

: In any case, you will be unlocking things in Halo 4 until you reach SR130,
: and this represents a huge time sink, literally days worth of gameplay,
: and it can take weeks or months to reach said rank if you don't play all
: that much.

That's just not true. After rank 40ish or so you have unlocked all the weapons. If you are talking about unlocking armor, then that weirdness started in Halo 3. Though Reach's system of unlocking based on points (the same way Halo 4 does it) is annoying to me.

: As I mention in my review, if you only have the time and/or
: inclination to play only a few hours of Halo 4 a week, you will be at a
: disadvantage against those players who have sunk more time into the game
: until such time as you've unlocked everything.

No. Unlocking everything does not give you an advantage. It's not like the more available weapons you collect will make you a better player. I still have tons of weapons / grenades / perks that I haven't unlocked and I don't ever plan to.

The carbine fires faster than the DMR, making it more useful to players with bad aim. The Light Rifle is a 4 shot kill when zoomed. Surely you have noticed this.
The Shotgun is ALWAYS more powerful than the scattershot. Scatter fires faster however so again, if you have bad aim it could be more useful. Think of it like 3 levels of shotgun: Bolt, Scatter, Shot.