To be fair, this is probably a wise decision given how badly Wanderers plays (like all the other lousy RPG/Platformer hybrids of that era; save for Zelda 2).
Anyways, I’d definitely say that Ys Seven is the longest and most standard RPGish out of all of them since you’ve got seven playable characters, the need to collect farmable materials to acquire new weapons and armor for all of them, skills that level through use and are learned from said equipment, and your usual elemental dungeons first half/revisiting said regions for other dungeons second half. That said, the game engine is roughly similar to Oath in Felghana, the boss fights are generally top notch, and the soundtrack is as rocking as usual. Its definitely one of the games that made getting a PSP worth it (as long as its a 2000 model or better since the last thing you need is a ghosty piece of shit screen for a high speed action RPG).
Ys Origin is sorta the in between for Oath and Seven since it moves away from Adol in favor of delving into the backstory of Ys. You end up having three different characters to play through the game as and its a little less adventurey and more sudo-dungeon crawler since the entire game takes place in the Tower from the end of the first game. That said, its basically Oath if Oath wasn’t a remake of another game and allowed to do more of its own thing. Its also really tough on the higher difficulty levels. Its also Steam only right now so getting a plug and play controller will help a lot.
The only other games that I’ve played are Oath on the PSP (which is an excellent game), and Ys 1 & 2 for the TurboGrafx-CD(emulator on the Wii’s VC).
I also have Memories of Celceta, but I don’t have a Vita yet so I can’t exactly play it. I’ll probably post about it in the “What games are you playing?” thread once I get a Vita.