31 Votes in Poll
The best and by far most impressive thing you could do would be to write an actual physical letter (not an e-mail): something that shows you are willing to put genuine effort behind your campaign to encourage the network to extend the show. Even better, you could do the same, not only to Disney and the show's creators, but to its sponsors as well. Networks and others respond surprisingly well to letter-writing campaigns. Be as upbeat and creative as possible. Remember always to be respectful, and NEVER to threaten. If you write the sponsors, always suggest that you have patronized their product after hearing about it during the show. Petitions, in my experience, are practically useless.
It wouldn't hurt to try but I doubt it'll work. Here's why:
1) When people pitch their ideas for T.V. shows, they pitch the story line for the entire show, so the first few seasons won't have any plot holes. Take Steven Universe for example. Rebecca Sugar would have pitched everything to Cartoon Network, like Rose Quartz actually being Pink Diamond.
2) Almost all Disney T.V. shows only have three seasons. If this rule is ever disregarded, then it would most probably be because every episode (save the very last, near the show's finale) would be it's own individual adventure (an exception being two-part episodes). This is why Phineas and Ferb went on for MUCH longer than three seasons. Other shows like this are Teen Titans Go! and the Amazing World of Gumball where no episode has a lasting effect on the show.
Of course, don't be discouraged by this; I'm only listing reasons why a possible outcome might happen. I personally think that you should go for it, and go along with the above user's idea to hand write a letter, since it might be more effective. Try getting a bunch of your friends to write letters to (ask any friends abroad to do this too, since heavy global demand is usually effective). You can ask people on discord to do the same, and request that the moderators make this a new event/channel, to make it official. You can make a Facebook event too, like the Area 51 raid. (If you don't have Facebook, as me to do it, I have a fake Facebook to save all my games and accounts and stuff) Bombarding Disney with handwritten letters is something I'll be looking forward to seeing on Buzzfeed news soon!
I don't think any of these options will work though. The show is set to end with season 3 and it's supposed to lead up to 'Tangled ever after' hence we went saw decorations..so...….yeah....
It probably depends on how this season ends.
What do you think?