I agree with you right now Maria cant complete the grand slam. She has been so far outclassed by Henin-Hardenne in their matches on clay I cant imagine her winning the French Open right now, as if winning the other three wouldnt be enough of a challenge for her after going slamless this year! BitterBlueBong might end up being right in fact, and that she will not ever be a serious candidate to win the French. Time will tell the tale.
Pierce is certainly not Grand Slam sweep caliber even if she had a chance at all 4 (which she doesnt IMO), even in her long prime of 94-2000 she won only 2 slams and her career high is a brief #3. Anyway cant see her winning Wimbledon, she probably has a chance at winning 3 of the 4 if she mantains her current commitment level and the top of the game remains a bit wide open amongst a spread of players, although she is an underdog as far as winning each one, but I dont know if she can win Wimbledon where she only has a couple ever good results, and her mobility is not good enough for grass IMO. Davenport's mobility isnt great, but it is a bit better than Pierce's on grass IMO, Pierce's power and first strike ability make her dangerous on grass, but her movement is insufficient to win it all I feel.
I agree the Serena of old could have done it, I am anxious to see how she looks to start the new year, but how much will that tell us, she looked reasonably good and back on track to start last year didnt she?

I do believe Venus has a chance to do it next year, if she continues along the way of the enthusiasm and renewed commitment she had to end last year; Henin-Hardenne also isnt as strong a player as 2003-2004 IMO even on
clay, obviously good enough to have a chance to win everything on clay if nobody plays better(last year)but vurnerable enough to improve Venus's chances to win the French IMO.
Cant see Clijsters winning Wimbledon, she could make a run, but not quite to the very end IMO, and she still is a 22-year old with only 1 career slam keep in mind, premature to consider her potential Grand Slam material for me anyways, others might be more bold however.

Davenport cant see ever winning the French, last year was the best opportunity she would ever have, and she still didnt really seem to feel that urgent about going after it, anyway as strong as she has been the last 18 months she still has to get over that hurdle of even winning a slam again, something she hasnt done in almost 6 years. Henin definitely wouldnt see winning Wimbledon with atleast a couple of Sharapova, Davenport, Venus, and Serena presumably playing very well next year around the summer; and if she doesnt pick up her game substantialy from this years form, she isnt even a threat at the Australian or U.S Opens. Mauresmo? ROTFL! Good win for her to end this year, if it translates to winning a slam next year(and I personally dont see it happening)she will be thrilled. Kuznetsova? I think she has another slam in her somewhere in the future, but a calender Slam, no way, and definitely not next year. Dementieva? Ditto Kuznetsova, except for the "another" part. If she keeps the progress she showed on her serve she might have a slam title in the near future if she gets the right combination of events, but she sure didnt impress at the year-end Championships.