Negima! is popular enough, but in Japan as in the U.S., Naruto and One Piece are MUCH more popular than Negima!. Look at the top-10 selling manga in Japan for 2008 and notice the #1 & #2 spots.
http://www.animenewsnetwork.com/news/2009-01-02/2008-top-selling-manga-in-japan-by-series
No Negima!.
Now, the first animation company completely jacked up the adaptation. It wasn't a matter of catching up with the manga as I see it because the manga was well beyond where they stopped. Indeed, a lot was cut from the Kyoto arc to compress it down from three volumes to two episodes. So there was plenty of material.
However, from the start, Xebec did a crappy job of even animating the thing. What FUNimation acquired was the updated version that was released on DVD in Japan because Xebec had to go back an re-animate whole scenes and supposedly all of episode 2. As I look at things now, with the unsatisfaction expressed by Akamatsu-sensei and others, I believe that Xebec knew they were not going to get a greenlight for a second season or series and so just did whatever they wanted, including make their own ending.
SHAFT came in and they weren't going to pick up with what Xebec left them, so they did their own story. Negima!? started off with me thinking it might be a darker, more interesting version, then changed into a comedy piece, which I found pretty funny at times. Then it brought in its main story, which was boring and the humor began to become tedious for me. Only the character of Motsu was worth anything by the end of Negima!? IMO.
So as fans are concerned, you've got fails (and I saw a bit of the LA adaptation and was unimpressed).
The new OVA's are faithful to the manga, though not as nicely animated as one might like.
In the end, if an anime were to be done, I think it should be redone from scratch and given a decent budget. With the global economy, I'm not sure that would ever happen. Sponsors may not be inclined to support more Negima! since things haven't panned out that well thus far as I see it.
Well, at least there's the manga.