I'm in the process of reevaluating my opinion on Halo 3's campaign by replaying it right now (although fuck this Etch A Sketch aiming I swear to Christ), but CE's Flood were just loads of fun. Starting a chain reaction of popcorn explosions with a single AR bullet was great, the way the Carrier forms would blow up and toss everything in the vicinity around them was fun, and the mindless zombies were okay to mow down with a shotgun in moderation.
The Prom Knights are just kind of annoying, especially with a Watcher around. My ammo just tanks when one spawns the other then requires more shots after shields being knocked down and blah. Teleporters with invincibility frames are just irritating to deal with.
Yeah. Before the Prometheans were revealed, 343 talked about how they were working to create new enemies who worked together in interesting ways on the battlefield. And you cans see how they did that with the Prometheans.
But the problem is, there's an absolute hierarchy to target. The Watchers 1) catch grenades, 2) regenerate Knights and 3) spawn Crawlers. Therefore:
Always. On every encounter, no matter what.
Then it's a matter of clearing straggling Crawlers or plugging enough damage into Knights to move on.
Bungie had that kind of relationship in the Halo games, with the leader mentality of the squads. Kill an Elite, and sometimes the Grunts assigned to them fled. But not always! Sometimes they charged. Sometimes they busted out suicide grenades and came running. And the fact that they behaved this way did not mean it was always better to take Elites out first. Sometimes it was better to pick off the lower threats so you're not distracted going one on one with that final Elite. There was no "right" way to take them out.
Likewise with the Flood. You could use the Carriers as portable bombs, detonating fallen grenades, popping packs of Infection forms, or killing Combat forms. You could choose to ignore the Infection forms until you cleared out the real, huge threats. Or mix it up, depending on the encounter and situation. Again, no "correct" way to fight them, and there was an interplay between the forms.
With the Prometheans, there's an order at play. SHOOT THE WATCHER FIRST, why would you NOT ever do that? I never once saw their grenade tossing ability, since I saw that during the E3 video and it was made clear you should kill them first. Toss in their other abilities, and it's downright fooling to do otherwise. And there's not a reaction from the other enemies, that I could tell, to their types getting taken out, as with the Covenant. Just a hierarchy to whittle down.
And worst of all, the Prometheans showed their bag of tricks in the first encounter. It was a great fight: was scrambling for weapons, flanking like mad, using the auto sentry as a distraction. That first Promethean fight was a highlight of the Campaign.
But then the next fight played out the same way. And the next. And the next...and the only things that really changed were the sheer volume of Crawlers in the mix. It grew tedious as the Campaign progressed, and the last mission felt like a complete chore, since there was nothing new on the table at that point.
So arriving at a Spartan Ops mission where it opens with two huge waves of Crawlers is a real turn off. And only served to remind me how tired I got of them in Campaign.
