I believe black and white 2 had a challenge mode but unlocking it was a massive pain in the ass.
But apart from that yeah no other difficultly options the games just got easier and easier.
There was a "Hard mode" technically, but it was beyond frustrating to unlock, and even then it didn't really change anything.
I don't remember which game had which, but basically if you completed either Black 2 or White 2 you received an item that allowed you to set up a game in either Easy Mode or Hard Mode. Apart from the idiotic fact that Game Freak was also gating Easy Mode behind completing what is effectively "Normal Mode", you needed to mess around with multiple cartridges to apply the item to another copy of the game in order to actually use it (you couldn't just tell your game "Hey, I have unlocked Hard Mode, I want to start a new game in Hard Mode". Starting a new game without saving the item on a different cartridge would immediately wipe out your save file, including the Hard Mode item, which was then lost and impossible to use).
On top of that mess, Hard Mode was not even really any harder. What it did was giving NPCs higher level Pokemon, but due to the way EXP worked in Generation 5 you received more EXP the larger the level difference between your Pokemon and the opponent's, so in practice whenever the game was supposed to put you in front of a level gap you almost immediately caught up in terms of level, and in turns also ended up unlocking stronger moves earlier than in a normal game.
The whiners have no clue what they're talking about.
Digimon Story Cyber Sleuth not only has exp share by default, it gives exp to digimon in the training boxes - including during sleep mode while the game is not even being played!
And this little piece of trivia is in any way relevant to the discussion at hand because...?