Nissan was world renowned for its design. There was a design center in La Jolla, CA, where they came up with the most innovative designs. After the merger, they forced design to move to manufacturing and they lost their edge. 

I think we would be seeing better looking cars from Nissan, not to mention better quality. 

Their cars wouldn't look like a Clio or Fluence

You would have married your high school sweetheart, Biden wouldn't be president, and Scotty would be driving a Fiat 500.

We would have seen better quality vehicles from Nissan.

What was Nissan's financial condition at the time? Would they have survived without the merger? (I don't recall and am too lazy to look it up.) Looking at a past Renault merger, when the French company bought into and took over AMC here in the U.S. it resulted mostly in crap products like the abysmal Alliance. However AMC would likely not have not survived as long as it did without Renault's cash.