As you pointed out, the difference between Pokmon EX and Pokmon GX is that the former ones are always Basic whereas the latter ones are always the stage they are supposed to be [1] (except for Tag Team GX cards which are also always Basic)
In a normal set, maybe one card would see a price increase, but if Merfolk succeed in Standard, a whole bunch of cards from Rivals of Ixalan will be in demand, including Merfolk Mistbinder, Silvergill Adept, Kumena, Tyrant of Orazca, and perhaps something like Jadelight Ranger or Hadana's Climb as well
In this case, you might want to put lessons in your sideboard so that you can find them with the learn ability
Of course, its biggest selling point lay with its namesake: this thing obliterates planeswalkers
This is a new rollout from Ravensburger will see Goofy and Max taking a magical detour
Before long, it became difficult to keep up with all the new effects, so if you came back for a couple of duels, you'd often spend most of your opponent's turns trying desperately to read a text box while watching a time-consuming combo wipe out your basic cards
