I think it depends. Action/RPGs can succeed with a weak story, and so can tactical RPGs ala Shining Force and Tactics Ogre. I haven't played any Langrisser of any kind, but I suspect it would probably fall into this category as well. For the jRPG format where you wander around on a map and get into random battles, yeah, the story is more important and you can't totally scrimp. Then again, early computer RPGs were lots of fun and were often weak on the story side and yet they did very well, even influencing jRPGs significantly.
Ultima isn't weak on the story!
Alot of old RPGs literally are just menus. Dragon Quest is
still just menus basically. Pretty much every PCE RPG is just menus and clicking. So, if you aren't getting anything out of the story, you're basically playing MyFirstRPG
tm and getting no story elements for the most part.
"I clicked and stumbled my way through *insert rpg here* isn't as fun as "Man I finished it and liked the story!""
I play RPGs for the story. If the story starts to get really boring and dumb, I shelf the f*cker and go play something else. I don't care if its the greatest game system ever conceived, if the characters are lame, and the plots about as interesting as a golf tournament, I don't play it.
my point is, in the time people can spend waiting for MAYBE one game to come out, they could manage to read the Japanese for at least 2, probably. Some of these games are not that long really. So you get more games completed, experience the actual story (even if its a kindergarten reading level/speed like how I roll!), anndddddd you pick up on some noodlecart moonrunes at the same time.