While it would be a lifelong dream to see Animorphs make it to the big screen, it does have a lot of things going against it.
Really, I think the best thing that it has going for it is going on right now: a re-release of the book series, generating new interest. I don't really know how well they are doing in the book stores, I think if KAA actually rewrote the series (as in, redid the books that the ghost writers did) then the popularity would explode with both people who felt disappointed in the series and those same people wanting to get their kids into the series.
I think as a Fandom, Animorphs has a really solid base, the problem is it came out in a time when fandoms were just being born to speak, when internet was new and fanfic was basically unheard of. I think if the series came out at the same time Harry Potter did, then it would have been as big as Harry Potter. Even scholastic/KAA said they were surprised that the series survived as long as it did and I can vaguely remember an interview saying that she didn't know why fans were still buying the books late into the series. (Which may be why she kind of rushed an ending because she wanted to write other series.)
But as it is now, Animorphs is really eclipsed by other, newer fandoms because they had that strong base right off the bat.
So, I guess to finalize my TL:DR, there can be a little bit of hope for the series to be put on the screen in a not-so-fail fashion. It's hard to tell what will hit the box office next, some movies have put famous books and books series on the screen, and if an entrepreneurial director saw the potential in the animorphs fanbase they might pick it up. What it would take to prove to them that it is worth it, I'm not really sure, I bet a lot of that is going to depend on how well the book sales of the series are doing now.