Most people only dislike red because of the lack of decent early game transport. Freighters/Landed smalls are pretty hard without a shadowbat/worm/turtle.
Yeah, I could see "lack of early game transport" as a thing with red: There isn't really a transport that hauls more guys than your Airbus in there. On the other hand, I was already used to the 6-man team, so expanding beyond that didn't feel pressing, especially after Metallo.
I guess I'm biased to early game codexes since there's a lot of good stuff mid-game that isn't linked to codexes, like blitz armor.
I am not convinced Blitz armor isn't endgame. I still use Blitz armor clear into the endgame, because the next competing option is -25 TU. That's an extra 6+ tiles of ground you're not covering, which can be the make or break difference between introducing your opponent to the sharp blade of your axe and being unable to advance at all because you can't make it to the next cover. Blitz pretty much sits for me at the ideal balance between protection and speed. I'd like Swiftsuit even more if the inventory wasn't too restricted to carry a useful loadout, and Gold shield wasn't a worthless pile of junk not worth the cost of construction.
Blitz even has blue shield. The best kind of shield, as it is STRONK vs. both Piercing and Concussion, the most common and the most deadly damage types respectively. It only fails to provide protection vs. Daze, Bio, and Chem, but Daze isn't lethal anyway, Bio is uncommon, and Chem is both fairly weak (most Chem attacks have low magnitude), and highly telegraphed (Chem-spamming enemies are usually identifiable from the Strategic layer before you enter battle).
The scarab is pretty good for early game shootdowns of the weenies since the armor seriously cuts down on damage
Snake isn't too shabby at shootdowns, either: It's down one heavy slot, but it's got a shield, so you're often able to bring down enemies with no damage at all. Its only downside is its absolutely terrible internal layout, that apparently is full of unidentifiable holes enemies can shoot you through, and an unhealthy number of lights.
25mm cannon will take down necroplanes/wasps, 50mm/30mm or charger laser (green codex) will take down megapol.
I looked at Green codex and ultimately found it rather lacking.
Having Turtle AND Worm seems redundant, as Turtle covers all of your transport bases, leaving no real niche for Worm, since your shooting-stuff-down angle is covered entirely by Scarab already. Pestulator is just a double-down on what Biosuit already offers, and shares all of its flaws. Bonaventura seems largely inferior to Metallo, having weaker weapons, worse hull protection, and only +2 Dudespace. Saviour is similarly meh: The medkit is nice, but YOU are the one who is going to need it, and it cannot be used on yourself, since you've got no armor and a crappy gold shield, the worst kind of shield in the game, as its threat protection profile is good vs...well, absolutely nothing. It fails utterly vs. both Piercing and Concussion, which are, respectively, the most common, and the most dangerous. Every enemy faction fields at least one of damage types, usually both, so Gold Shields are worthless against everyone!
The main problem with the Green Codex is that it contains too much redundancy. Redundant equipment, redundant ship hulls. This kind of redundancy might be helpful to the Total Newbie, but not to me.