He is every bit as relatable as Indiana Jones or John McClane -- which is to say, not very much. They're by design meant to be very unrealistic.
These types of characters are archetypes everyone wishes they were if shit were to hit the fan. Most of us are never going to be treasure hunters or terrorism's worst enemy, but people watch these films and imagine how awesome it would be if we were. If a group of terrorists were tearing a building apart, I'd love to be a hero who gets by with the skin of his teeth and save the day while being clever and charismatic. It's daydreaming nonsense that is not weighed down by the reality of people who do the things Indy and McClane do.
Just because Drake throws a few jokes here and there doesn't make him relatable any more than Indy. They're just being unapologetic badasses in a classic hollywood way. They're both people who are extremely lucky in the face of danger and often can't believe how lucky they are, in addition to being naturally witty, smart, and athletically unmatched. Drake is an "everyman" every bit as much as Indiana Jones is a University professor who takes vacations killing Nazis who want to use artifacts for evil.
there's a pretty big difference when drake doesn't exist in our world. i get to see john mcclane as a person. i understand that he's a dude whose marriage sucks and that he's a cop. got it. raiders doesn't start with indiana jones as a professor, but you do see him among real people and there's even slower moments of deliberation with other real people before he sets off on the adventure within that film.
nathan drake is introduced to us in which he crashes a plane, or is stuck on a dangling train depending on which game you start with. at no point in uncharted 2 is he shown interacting with real people. at no point do i get him as a person or where he belongs in relation to my reality. it's more of a pure fantasy.
They're all strange and you can deconstruct all three this same way, or gloss over their weirdness with pithy soundbites like you did for IJ and Mcclane. All three are takes on the relatable, everyman-styled hero; they don't have superpowers, can all be caught off-balance and are just slightly more skilled/capable versions of people in the way we probably like to view our ideal ourselves, just trying to do the rightest thing in a terrible situation while managing to beat the odds seemingly by the skin of their teeth.
yep they're all the same. that is a good point and well-made.