Personally, I imagine they're somewhere inbetween - and it seems to vary from tribe to tribe. They're descended from hunter tribes that crossed the frozen sea long ago, after all, and they still have their many tribes, so they haven't exactly left that lifestyle. Yet, there's plenty of clearly intellectual ones, and they don't seem lacking in intelligence in general.
Then again, I'm probably biased, being that I RP a Scholarly type more than anything else. I figure you could play a Miqo'te as savage as you liked - nothing wrong with some individuality.