Care to explain why?
Sure. I sat in the cinema utterly gobsmacked at the "shitepile" that was AL III EN. It was so unlike Aliens, they killed off Newt and Hicks... all that stuff. Later - when I got over myself, I realised that (especially the Assembly Cut) that it was a good film (not in the league of the first two, but still) -- a good way to end the Ripley arc and all that.
Resurrection - it just seemed to me like a pointless entry. Its set 200 years later. They explain away things with "a big deletion." Ripley's back, but its not Ripley, its a hybrid clone. This was the really pointless bit - to get the movie made, they needed Sigourney Weaver - but she was already dead, so they ... you know what, I can't go on, you know the story as well as I do (probably better, its my least watched one of the series).
I think the worst thing about the movie (for me - all this is my opinion) is that its clearly a black comedy. Tonally, that's out of step with the whole saga. You could say that Aliens was totally different to Alien - and it was... but it still felt part of the same universe. For me, Resurrection just felt out of step. If the Aliens Saga were a TV series, Resurrection would be the musical episode.
I think the film looked beautiful though - the advances in special effects were on show, I thought the performances of Winona Ryder and Michael Wincott (SP? Doing this on the fly) were outstanding. The underwater xenos were cool too.
But that was it - the whole thing seemed a bit of mess, I didn't like that they made it a "French style movie" (look, I know Weaver loves all that stuff and I imagine that she was a big influence on getting the French team in), but yeah --- tonally out of step. And Whedon's "smart dialogue" might work for Buffy and glossy Superheroes but hearing Ripley's "Who do I have to f**k..." line made my stomach turn. And as has been pointed out, the Wal-Mart line was deleted - but its a great example of a "Wheedonism", I suppose.
I guess this was before we had the concept of rebooting franchises, but as I say - a French black comedy was something that I didn't feel fitted with the saga as a whole and if we had our time over again, I would have preferred a reboot or something set in the same universe that didn't shoehorn Ellen Ripley into it (though of course, we know she was only in it to get the finance -- and as the one producer of AL III EN said "You could have someone pissing against a wall for 90 minutes and call it Aliens and still make 30 million).
Anyroad - those are some of the reasons why. :-)