a couple of things -
I started as tech back in the demo of u2xmp, and dreamed of that day my computer would have enough fps to let me play ranger, once i built a gaming box, i just played the hell out of ranger for months.
Ranger does tend to draw out the 'die-hard' psuedo-obsessed gamers due to its characteristics. It requires the highest level of skill in reguards to movement and natural reaction time for weapons. It's the fastest class and natural skill is directly reflected by the single point precision it requires. It is also a class that I think takes more time to master then the others. Phat made some good points about the transfer of ability betweeen the classes, but after watching the veterans of xmp change class, i think I'm believing more strongly in the fact that, if you're sick at ranger, you're going to be top notch at the other classes.
on a side note, i remember playing with [pet]puppy, who we all know is gunner 99.99999% of the time. we were in this server and there was like 3 minutes left on garden. he was of course playing defense as gunner, and i was about to leave the base in a raptor. i told him to spawn as a ranger, as we needed to get the last 2 arties asap. after some denial, he agreed, and we raided the arties and won the game. afterwards he was like, "that was scary, I"m never doing that again". This just goes to show that some classes just might not be someone's cup of tea, that doesn't mean they couldn't be masters in it if they wanted to.