Gems- because too powerful? Idk. Guess they weren't balanced. This new Z-move sounds like GF's new system to balance it out. Improvement.
game corner was boring slots gamble that should have taught you that'll you'll never win playing that shit. I used to grind the e4 for money to just buy the coins directly for the tm's and pokemon I wanted. Coin flip was fun but consumed more time than it was worth. Now they have you fight pokemon battles for bp in order to earn stuff. improvement.
annoying 24 hour limitations were annoying. now you can buy better versions of those balls without the wait. improvement.
safari zone- that other gambling area where your stars had to align to find AND catch a chansey in there without it running away like a champion track star. remember that footstep limit? then we got the friend safari where we could battle and farm for pokemon with 3 or more perfect IV's and hidden abilities. improvement.
extra pocket? what was that for? the reason I didn't notice it is probably the same reason I won't miss it.
Not that you needed it unless they happened to get a crit. jesus saves. often. and always right before obvious rival battles.
Seasons? I literally don't remember them. What was their point... on yeah, sawsbuck forms. and then no one cared.
Follower pokemon were a nice cosmetic. kinda wish it had an on/off switch.
Edit:
As for that 'leak' thread. A lot of it sounds like it could be legit but it could easily be a troll post. fighting/psychic abra line- so it can use elemental punches effectively again? flame dancer marowak, volcano alola form golem... Like, you look at the answers he posts and you could really see it being true. Either this is all true or this is a very clever faker that has better ideas for pokemon games than game freak. not that that would be too hard.
Also, the fire guy with the Marowak reminds me of Marlin, but with an opposite personality type. But I really like the both of 'em. This should be fun.