That’s a hard choice…They’re my 2 favorite classes!
Warlock is a lot less common - so their utility is pretty well appreciated imo…nothing like cookies and summons 
If you care about standing out or being unique to your group in ways nobody else can - I’d pick warlock…
both are successful in all end game - so there’s no wrong choice here! I think druid is always a safer bet though, because they have a healing/tank spec, so there will ALWAYS be demand for you…whereas a Warlock will have to compete vs more classes to sometimes get invites.
