It's hard to say what the future of 3 packs are now. There is a possibility they'll return IF...

IF the 25th Joes don't go so well, Hasbro will need to find another way to make things work. Return to what works, it's possible.

If the 25th Joes DO well, then we can expect more and I'm guessing that they'll be in the new designed style. it's pretty much agreed that this is the last hard push for 3.75" for the time being.