The recent post on the Official TF2 Blog moderately hints that the next TF2 update could be for the Soldier. Also speculated by nerds on the internet is the possibility of a new "King of the Hill"-type game mode.
Now, this is purely speculation. For all we know, Valve could pull a fast one on us and make it be for the Demoman, and only wanted us to think it was for the Soldier.
However, we want to know who you, yes you think will be updated next. So, until August 20th, there will be a little poll box in the upper-left hand corner of this site, feel free to vote and if you want, leave why you voted how you did in the comments below.
Sometimes, Valve just makes my head hurt.