Each class has distinctive strengths, this thread shares what those strengths are.
Dragnonknight:
Target pull, close to medium range control and CC
Sorcerer:
Summoning and ranged Magicka DPS with an Ultimate that dispels and silences for 8sec
Nightblade:
Stealth! Siphon healing! Very strong when attacking from stealth
Templar:
Target Charge. Ranged Magicka DPS. Direct healing.
While you can play however you like each class does bring strengths and I guess some would have fun playing to those strengths.