Well I'm not opposed to longer posts. My last 1x1 partner wrote longer posts than me, but they were always filled with character development tidbits and lots of other great stuff.
I've been guilty of writing long posts plenty of times, but I usually tried to have them filled with plot advancement and other stuff pertinent to the story or character. I usually consider padding to be something like going into too much detail about certain stuff.

Give you an idea, here's one of the longer posts I've written on the new site: [url=http://www.roleplayerguild.com/topics/705/posts/ic?page=1#post-63751]Link[/url]

I wrote what was essentially a short novella with one character on the old site. Just depends on my motivation with the story.