Cameron basically felt that it was a lot better than what he was expecting. In other words, he was pleasantly surprised.
I suspect he was imagining something a lot more superficial and comic-like (something very Michael Bay-ish), rather than a stab at grounding it in some sort of ominous historical mythos. Which, personally, I also liked. I think he probably understood what Anderson was attempting to do, even if he would have done it very differently.
Really, when you learn about how incredibly small the budget was, it's a marvel the film looked as good as it did. There are still clear problems in the narrative and it fails to emotionally engage most people, but when you realise they didn't even have enough money for all the characters to have separate flashlights... Seriously, they had to use camera tricks to make you think they had the budget for more than a couple of them.
I don't think the full story has yet come out about whether they had enough time for the schedule, either. I know that many of the problems with 'Requiem' looking rather crappy when it came to exterior action scenes, was because they literally had no time for more than one or two takes. We all know that the directors had some very bizarre ideas, but it makes you wonder if it would have at least looked better if they had been allowed the time they required for it.