I’d wait. On the off chance that the in hand pics of a complete devastator look awful, you change your mind and no longer want it anymore, it would be easier to sell the sealed figures for close to what you paid.

If devastator turns out to be awesome then saving them to open all together would be a sweeter payoff - all the figures will be fresh and interesting to you and you won’t have had a chance to get bored of them. (Bored isn’t really the word, something that’s been in your collection for a while can still be cool it just doesn’t have the same appeal as a new thing)

I mean, 2020 is only next year, it’s not long to wait.