When I say "campaign", I'm specifically talking about the mission quality, story is a separate metric for me since i'm a giant autist lorefag and as a result I view that extremely importantly Anyways, I actually agree with all your criticism's of 4's campaign entirely, it's just that, at least for me, the amount of flaws CE has due to the hardware it had to run on are even worse.
The limited amount of weapons + the limited amount of enemy types for most missions + the overuse of copy pasted coordior and map geometry (something 4 also has, to be fair), wide open empty areas, and finally then reusing the first few missions for the last half of the campaign for CE, at least to me, make it the most tedious and repetitive Halo single player experience, and the minimalistic story doesn't provide you much of a rope to tug yourself along with either.
That's not to say CE has a bad campaign, it's still really fun, in fact, more fun then 4's, i'd argue, but it's also more frustrating then 4's. I feel like 4 is, essentially, a less flawed, but also less oustanding version of CE's campaign. It's got similar mission templates (compare FUD to PoA, and then Requim to Halo, even down to the exiting the interior space and having the wide open vista) as well as a similar atmosphere and, relative to the other halo titles, both 4 and CE have more synthy stuff. (though, of course, marty's work is superior).
At the end of the day, I think it comes down to if you want a sligtly more polished experience that's more middle of the road (4) or a slightly less polished expierence that has higher ups but also lower downs (CE) for that,
All of that said, I think we can both agree that regardless of that 4, should be better then it is. Even if it is as good as CE campaign wise, it came out 11 fucking years later, it should be way better then "as good".
5 got a fee w10 port for it's forge and MP a few months ago