As if Keyboardmania and Rocksmith are seriously hard enough, how about you try the REAL PIANO/GUITAR yourself? If real drums are manageable enough compared to Guitar, Bass or Piano which may seem to be harder, other challenges may probably include the cordination with other stuffs as part of the band. In fact, it may look like the DJ-simulation rhythm games have been going in the opposite direction even today compared to some of the dance games which actually make use of the entire body, pose and motion thanks to Kinect but the technology still isn't perfect as most of the dances are suited for individuals or duos depending on the song.
In fact, I should feel ostracized by how Beatmania IIDX series goes nowadays with irrelevant themes which don't belong to DJ land that well and especially that Nostalgia decreases the difficulty Keyboardmania series has. Sure, there may be tons of keys but to repair/replace them will be tough in case of hardware damage. That is one proper complaint, unlike the complaint about how hard the game is.
Nostalgia is trying to be like Deemo in terms of gameplay. Although the design of the controller may look like mini piano keys, the way you tap the keys to the corresponding notes is akin to Sega's Chunithm series. Sure, that also has the elements of Deemo but it has more than that like air notes which make use of sensors to see if your hand is in the air or not.
Well, at least Konami has rebooted Keyboardmania but in a weird but less difficult way. The game may be fun but extreme difficulty of playing a real piano is still there. One better thing is that Marasy has become more famous than before for being involved in Nostalgia due to his piano cover videos. He's also famous for playing Bemani songs on a piano as well. You can check out his YouTube channel if you're interested.