I found HL 2 a bit boring (episodes got progressively better), but let's get back on topic:Alanschu, will my team be effective if I choose to play with a warrior, a dog, an archer and a healer, or are damage dealing mages a must have in DA too?
I find a balanced party tends to be the smoothest playthrough. The party you describe would probably work pretty well.
Mages are very useful, but they don't need to be damage dealers to be useful.