I don't know... It's kinda selfish for my part, but I just wish Takara or Hasbro will stop reissuing G1 toys. That's the reason why I'm selling most of my G1 toys, I'm afraid that TF toys I kept will no longer be rare or unique even if it's original.
In the case of Transformers, I have to strongly believe that you should have absolutely no worries about that.
Lets use Predaking as an example: There were the individual box sets, then the first Japanese gift set, the second (first reissue) Japanese giftset, and the third (second reissue) Japanese giftset. The first reissue, in terms of the giftset, was the same packaging but sported an additional label. The second giftset not only sported a completely new box, but also sported what some might refer to as the more "cartoon/anime accurate colors" for the characters in the set.
Beyond that, Takara has a long history of making subtle differences when it comes to reissues. Be it Ginrai or even Henkei! Hot Rodimus. They always try to make the differences be tied to everything or anything from subtle paint/color differences to both the boxing and how it was packaged.
In other words, while I nothing when it comes to Hasbro's work with the franchise these days (besides the difference they do when they issue their own version of certain characters)... I can reassure you that if they do an Encore of Galvatron, Sixshot, Fortress Maximus, or any other character we are clamoring for, they will have changes that keep your collection from losing their uniqueness and value.