All Right people, let's use logice.
!st Gen- Color
2nd Gen- Metal
3rd Gen- Gem
4th Gen- Carbon( Diamond is mostly carbon and Pearl is somewhat Biomassive and bio mass must consist of carbon.)
5th- By the recent pattern, 1 and 2 were colorized, 3 and 4 were birthstones, so 5 and 6 must be related in another way.
Which means we can't expect colors and gems anymore.
We can assume it will be sun and moon, has to do with space, but only if gen 6 has to do with time, as if those were deeper meanings into Diamond and Pearl. All we need a new Starters, legends, raries, some newbies, and almost no evos. Without new Pokemon, the anime would have to come up with a new plot other than Pokemon meeting... Which is good so scratch Newbies. I know it's too late early to think of Gen 6 now but somehow with the pattern, it should have something to do with deep space or time.
Unpredictability isn't the only option. I know the anime did this table turn but did the other franchise do that? No. I mean, I've seen people in my early childhood that said it was very predictable Togepi had an Evo (Altough not what they expected since they thought he was "Evil")
I've made some of my point, I'll be back.