I was actually discussing this in a Skype chat with a few other Ness mains and we thought it be something very interesting to try out. I can see this new 'amiibo fighting' to be a sub-branch of the normal pvp-tournmant style, instead of honing their own skills players would instead have to teach their amiibo new techniques. Teach them how to counter each playstyle, finding the most optimal approach, different types of combos and if you're feeling cheeky they can taunt after each KO. There are so many different things each amiibo can be taught, and if these amiibo tournaments turn out to be a success you could branch out to other game modes such as coin battles that are usually not played competitively.
Amiibo also allow players would can't handle stress very well an opportunity to participate in competitive smash. Let's face it, not all of us are able to deal with stress, and even for those who can it is very likely to affect how you preform at tournaments. But with these amiibo you don't have to worry about a thing as training the amiibo is the only difficult part, once you've done that the amiibo does the rest of the work for you. The idea of having an amiibo support you in a 2v2 is also fantastic, you could teach it to do certain things such as using projectiles on you whilst you PSI magnet or to combo off of throws that you cause.
I swear I'm not an amiibo salesman but I really do think that there are an incredible amount of possibilities and with it just being released we've barely scratched the surface of the metagame.
