You will want to be level 6 by the time you leave the first part of Broken Valley. I was able to do that, although I now know which ones are worth mind-reading and which ones aren't.
Hmmm ... I was doing ALL the possible mindreadings and ALSO reached level 6 or 7 when I leave teh first part of Brocken Valley.
And further on, the so called "not important" mindreads have a
low XP dept!! So if you mindread all NPC etc ...
the difference between only mindreading what you give a skillpoint/statpoint or some extra loot ... or mindreading ALL
isn't highAND, also, mindreading is FUN

and give some extra humourous dialogs !