I brought up the Bob Marley Ensemble because its a genre that requires study in order to sound authentic, much like any other style of music.
Its much better to look at it by genre. I want you is a pop rock song, there are much better bass songs for pop rock out there than the Beatles. Beatles are a great band of song writers but i wouldn't label any of them 'greats' on their instrument. IMO you'd be better off doing a Leland Sklar transcription. Lemon Song is the most basic of blues not so far removed from ZZ Top. You'd be better off check out some Robbin Ford. The Boss by James Brown that bass line is weak. Check out D'Angelo's Chicken Grease thats some funky stuff
"I Want You" by The Beatles a "pop rock" song?!?! Yeah . . . it's such a "catchy" Beatles tune!
Please . . . if anything it's quite bluesy.
As for the 'great' player debate . . .
I stand corrected by what I wrote earlier. You put pretty much all emphasis on technical virtuosity (specifically Jazz and Fusion) to define 'greatness' and that my friend is only a slice of a very big pie. True. McCartney doesn't slap, pop, tap, double thump etc. but his bass lines are some of the most melodic and well thought out out there (in his genre). Also, try playing and singing some of his songs at the same time. You'll find out that some are downright tricky.
I'm sure you would agree with me (and the whole bass Universe) that Jeff Berlin an indisputable bass god. Well, guess who his original bass idol is? Jack Bruce, which according to your standards would not fit in the 'great' player category. What about Jamerson?
How many players out there have technical prowess? Go to youtube and you'll find quite a lot (alongside a large amount of mediocre ones)
Now, how many players out there have unmistakable and memorable bass lines? Much less.
And those who combine both? Even less.
Catch my drift?
I like, practice and apply technical stuff as most people do, but you won't get hired in 99% of gigs just because you can double thump 32nd, 64th and 128th notes. That's one of the most important things they teach at Berklee.