I come from a videogame background in MMOs and FPSs, and I've seen both sides of balance responses.
MMO players are so used to seeing things buffed and nerfed that while they dislike changes that hurt their characters and will complain about them, they are the first to "get over it", as in the first players to adapt and move on. They know that when their thing is broken, its going to get fixed and they need to move past it to succeed.
FPS players (specifically CS players) despise even the slightest change to anything at all. The slightest change to pistol damage or AK reload time, or the movement of a window two inches to the left (all of which have an admittedly large impact on high level gameplay) is reacted to with heavy backlash, and that backlash has gone so far as to fracture the CS community between the three games.
I have a point here. My point is that you can chose which of those players to be, and when you are playing a Demo, it's greatly to your advantage to be like the MMO player. When your character gets changed, think about it not as "Did my character deserve this change? It's negative and i don't want nerfs to my character" but instead as "Did the play style of my character get changed?" If it didn't, then it's a simple matter of adapting to the change (and in theory, you're playing your character because you like how he plays and NOT because he's good) and if your playstyle HAS changed (as in, Sonic 2.5 -> 2.6) then you have a right to question the validity of the decision and reevaluate your decision to play that character or that game.
I'm going to take the liberty of assuming you like Fox for his playstyle and not because he's good. That being the case, you should be glad that he plays exactly the same in 2.6 as in 2.5, and instead you can use your time to pitty Oracle who lost his ROB playstyle or Kink who is still mourning the change to 2.1 Zard Nair.