Uhh let's see...there's no more trading or Legacy format (HGSS cards are getting nuked) pack codes still work but now you can also buy stuff directly through micotransactions, cards can be dusted like in Hearthstone for credits to craft new ones...there's been some talk that apparently chat has been removed entirely, but in current PTCGO you can only chat with friends anyway, they removed random chat years ago. One of the other pros is that it does appear to run faster in terms of animations, but the whole thing is obviously built with smartphones in mind. If you look at the screenshots on Serebii, there's tons of wasted horizontal space in the desktop version, the whole field is aligned vertically for phone play and follows flat design trends rather than skeuomorphism: www.serebii.net/tcglive/pics.shtml It's basically just Shadowverse/Hearthstone/Vanguard Zero with a Pokémon skin now. I know some players are excited for that, but I went hard into Shadowverse a few years ago, got seriously burnt out after like a month, and one of the things I liked about PTCGO by contrast was how different its progression and systems were.

It's a similar situation to GTS in that the system was most reliable when you put up your own trades rather than search someone else's. Also like GTS, there were a lot of "go-between" traders making the economy function--person A trading with B so they can trade B's offer to C because they didn't have what C is asking for. I think in both cases, that wasn't really anticipated by the developers as part of the intended design, but emerged by necessity. The pack trading is what sticks out to me the most about PTCGO's trade system because the packs themselves weren't tradable in other games like Magic Online (iirc they were mainly for drafting? it's been a while) but this effectively injected a new currency into TCGO every couple months--and the rotating standard format served to debase old currencies over time. It prevented a solved economy from emerging, like Diablo II or the older MMOs. People could still hoard over time, but their hoard's worth fluctuated enough to keep them active and participating in the current economy. That's a relatively rare achievement for an online game.