Queen defeated the Beatles in the last tournament?
Yep I'm going to have to participate this time around to see that doesn't happen. I love me some Queen, but umm....well I guess I'll save this part of the post for the upcoming tournament
As for which option to go with, option 3 would be "something different" but as people pointed out there's lots of flaws with the idea. Like people have pointed out, who really cares about the "greatest bassist?" You've got John Entwistle, Flea, James Jamerson, Bootsy Collins (if funk and R&B artists will be allowed in the tournament), Les Claypool, Chris Squire, etc. Great players, but overall not as interesting to discuss as guitarists, singers, or even drummers. And of course arguing for individual players just isn't as interesting as arguing for bands and their entire body of work and legacy on rock history. I don't want to debate whether David Gilmour is a better guitarist than Brian May. I want to debate on who is a greater band, Pink Floyd or Queen.
As for the genre or decade option, both could be potential problems as you could make an argument for the Rolling Stones, for example being in the 1960's and 1970's portion or U2 being in the '80s, '90s, or '00s portion. But genres really complicate things, as genres are such a subjective thing it's very confusing. The Beatles for example could be under psychedelic, folk rock, pop, rock and roll, etc. Rush could be under "Progressive Rock," "Hard Rock," etc. I could be getting too technical here though, as I'm not familiar with how previous tournaments were set up so I don't know if you guys are that specific with genres. But yeah I think you get my point.
I think decades would be easier to determine and more organized. If you simply go with the idea that each band will be put with whichever decade they debuted with you're good then. No one can dispute that the Rolling Stones, Led Zeppelin, and the Who started in the '60s and also had success in the '60s, so put them in the '60s region. And in some cases you could put a band with whichever decade they were their most successful in. Nirvana, for example debuted in the '80s, but clearly they are a '90s band.
If you go with decades, you have two rules to easily set up your "regions."
1. Each band should be put in whichever decade they were the most successful.
2. If a band was successful in more than one decade, simply pick which decade they debuted in. (ala Zeppelin, the Who, Aerosmith, REM, etc.)