JRPGs have been influenced by WRPGs anyway. D&D is the granddaddy of all.
FF and Dragon quest? Influenced by D&D.
WRPGs are better because they can reward exp for doing things other than just mindlessly killing monsters. WRPGs are better because character customization has been more dictated by the player's choice rather than the game just deciding it for you. WRPGs are better because much of their stories can be developed solely by your own choices. Instead of imposing narratives, they present narratives that you can choose.
So WRPGs are more preferred.
Of course, I could also list several valid reasons why JRPGs are more preferred over WRPGs, but unless you want to read how many times I can say "they hold your hand while you play," it's not happening.
Back in the SNES, PS1, and early PS2 era, I would have said JRPG.
Now, the only JRPG I'll play are the Tales games (simply because I'm a sucker for that series and it's combat system) and the more unique JRPG games (generally the stand alone titles that have a more serious or thoughtful tone). Western RPG's just trump them in every way, from character customization to having more intricate, and interesting, plot lines.
The only JRPG games I've played this generation that I would say can stand up to WRPG in terms of story telling, game play, and customization were Tales of Vesperia and Tactics Ogre: Let us Cling Together. --- Each person might see a rose with a different shade of red, but the fact that we can all agree on is beauty -- that is a miracle. -Michea, FFXI
This is like asking which type of war movie is better, action or drama. Both have strong points, both have weak points. JRPG's tend to have stronger plots, WRPG's tend to have better character connection. --- If you love a person, it doesn't matter if they cheat. If you love a person, you won't cheat.
JRPGs for me. Ironically, I feel like they would be doing even better this gen if the devs had stuck to their guns instead of listening to the complaints of WRPG fans (the people who will never play Final Fantasy anyway) and altering their games to try and capture that audience. Nothing wrong with different sub-genres being different (and I do enjoy both). --- "The black wind howls. One among you will shortly perish" Magus