On "Somewhere in Time" wiki-page, if you click the reference link it leads you to an article which never actually mentions the term "synth-metal".
Clickling the link actually leads you to a wiki page which looks like it was done by somebody who had too much time on his hands, but not the same amount of effort.
Putting a heavy-metal album and a pop-song from the 80's with 2 lesser know bands from 3 decades later in the same sentance to define a term looks... amateurish.
Actually, if you look at the references at the bottom of the page, you can notice not a single article mentions synth-metal as a term.
I don't know how Wiki editing goes, but I don't think joint accounts are possible. This doesn't need a big discusion with some mods, maybe just one or two well-written report.