I'm a replicant then.

Maybe it's because the end wasn't an end for me, more a begining. That end was more like they could start something new again and I was downright happy to see them having a new chance. I'm probably the only one, but I would love a new movie, just to see how the live after this movie is about.

But, anyway, somewhere I read the best way to do a classic is done something like that time were the only chance you will have to do it. Always, in all the movies (Or video games, or comics, or books, or whatever). I guess that happened with the 3 Toy Stories: With the three they wanted to conclude the story of the characters the best way they could, because they didn't know if they will have another chance. So, I think, you didn't waste any words if they announce Toy Story 4, because I'm pretty sure is that happen is not because they planned it, because the people demand it, so, anyway they did the last Toy Story three times in a row.