Lack of mobility with excellent defence or great mobility with ranged attacks

Songcaller

What do you think would be better?

Slow moving with excellent defence or rapid movement with ranged capabilities?

Melee capabilities are better on the slow mover but ranged attacks can kite.

Ludullu_(NiKr)

All sides have some mobility and counters to it (some classes more some less) and a good range of defense on some gear, but you'd lose out on some other stat.

Dolyem

Mobility should definitely be a factor in balance.
Super tanky and high damage output? Least mobility to balance that wreckingball out.

Glass Cannon? Give them either high CC or Mobility.

It's all situational and dependant on the class identity and what makes sense to make a weakness while highlighting what their strengths are.

As for what would I prefer to play between the 2 choices you've given? I usually play melee so that one.

Songcaller

Okay cool. I went slow with excellent defence backed up with teleportation and speed spells. Melee mode extreme with only ballistas and wizards for range.