I think we will get some new characters, but Ian you should expect all the old characters to return...and it won't be a remake if the patterns are different.
As for making the multiplayer more strategic...boxing is very strategic but I really do not see how you can turn the punch out Formula into a multiplayer game. If you want to just have those characters selectable and have a more traditional arcade multiplayer boxing game, that I can see happening...but to me it would not be Punch Out, but something else.
But I guess it doesn't matter, as long as the single player remains intact and with the traditional game design it doesn't matter.