The most recent post that I found particularly interesting is titled Chess960 Equalizer (September 2013). It's based on a video whose content no longer works outside of Youtube, but you can watch it onsite: Guinness Basketball Commercial. It features a group of athletes playing basketball in wheelchairs. ChessRex founder Ernesto comments,
Chess960 is often called a variant. Chess960 is not a variant of chess because it is played by the same rules with the same pieces and executes to the same outcome as traditional chess.
Since chess is widely played by memory and recognizing openings and tactical positioning is key in becoming a successful chess player, knowledge will give you a great advantage over less experienced players. Chess960 evens out the playing field because there are 959 other starting positions including the traditional position used as the norm. Most players of high caliber do not want to give up their advantage over any player no matter what so they result in calling chess960 a variant or "not chess" at all.
To force or request a player to give up his memorized opening and positional recognition is like asking a basketball player to use a wheelchair to compete. All in all chess960 is not a variant or a handicapper but an equalizer.
While I agree with the comment about chess960 not being a variant -- and like the reason given -- I don't agree with the comment about it being an equalizer. In chess960 a good player has to think about the opening starting from the first move, just like his opponent. His understanding of positional play in the opening -- rapid development, piece activity, center control, Pawn structure, etc. -- gives him a big edge in reaching a position that he understands very well. That edge will remain after the transition into the middlegame.
Although many chess960 middlegame positions are unlikely to arise from the traditional start position, there are many other positions that could easily arise, especially after both players have castled. In the endgame, which is indistingushable from traditional chess, the good player's experience will guarantee a big edge.
Fun, yes; challenging, yes; equalizing, no. Chess960 has enough advantages that we don't need to invent new ones.