What makes a good LF2 Character?

[YinYin]

• fit into the environment and position it is designed for

(no balance or quantitative requirements really, just this one qualitative requirement)

That one point in turn leads back to this: http://www.lf-empire.de/forum/showthread.php?tid=8574 (for original LF2 being the requested environment)

And of course more general concept design depending on the position it's supposed to fill (hero, boss, support, ...).
Haven't we discussed that kind of thing before? If not I know I've been trying to explain it a thousand times.