Perhaps, but because everyone's feelings on an album are so different, you'll get varying opinions for either answer.
I don't think an album can be too long, but then again, I am a fan of longer albums, usually 2 disc albums (like nearly half of the albums by The Flower Kings). I think a longer album can mean a band/artist has more time to fully express what they want to say through their music, but fans may see some of it as "filler", which can be a problem with double albums, particularly concept albums.
I think for concept albums/rock operas/thematic albums/narratives, longer can be better. I think Genesis' The Lamb Lies Down On Broadway is the perfect length, and works really over the four sides, and over the course of it's 23 tracks, the band performs a well thought-out story through music and lyrics. I wouldn't say any of it is "filler" per se, but some tracks may be weaker than others (as with ANY album), but IMO, a band/artist wouldn't write a song if it didn't have some meaning to the overall story/concept/theme.
-Marc.