The original voice actors for the characters and the narrator were pretty good. It's nice to hear they'll be making a comeback.
However, I have to say - it might be good to, you know, give them more to say
The original Trine had the seed of a very interesting team dynamic between the... "Simple" but courageous Knight, intelligent but awkward Wizard and capable but elusive Thief. It was disappointing to see not much come of it. There's room for much witty and appropriate banter in the story, not necessarily about anything in particular, just so we can get a better glance into the characters' personalities through their words and attitudes.
My example of good character interaction through banter tends to be Left 4 Dead 2. We don't really know much about the characters beyond their names (and even not always that - "Coach"), but we get a very good idea of WHO they are just by the way they hold themselves and the way they behave, from Ellis' long-winded stories that never end to Nick's constant sardonic comments that keep getting him in trouble and so on and so forth. They could well have been blank slates, but they're given character by their interactions.
This is something I really wanted to see more of in the original Trine. We get a few good examples of this with the Wizard's comment of "This is interesting stuff!" a comment I'm sure we've all made at one point or another about an under-appreciated hobby. We also get a good example of this with the Warrior's "Save villagers or crush bones? It don't matter!" Some hero, eh?
That's the sort of thing that really works, which is why it's so frustrating when they spend entire levels not saying anything at all.
But that's just idle musings. It's great to see the original voice actors back.