This implies that not only does our mage observe his enemies before they see him but he also wins initiative to such an extend that he avoids getting attacked entirely!
And you imply that the archers have already spotted the mage, that they have their bows loaded, that they've won initiative, that caster isn't acting in the snap phase, that they're prepared to face a caster and exactly know how to react when someone vanishes before your eyes and many other things...
But, where is this going? I can't really see your point here, there's little
anyone can do against a group of archers, even a warrior in full plate, save take cover or run. And, again, casters have far more options than non users for doing so.
Also it should be noted that combat companion is not for fighters alone. All arms users and even a good deal of spell user gain powers from this source book an as such it is IMO the very best source book we have seen in years.
Yes, but it covers only combat. Again, with too powerful I do
not mean powerful in combat.
If it was only for mages blasting groups of foes with fireballs it wouldn't have been a problem. the real problem comes from the fact that they can also do a lot of other things.
The problem comes from lists such as Delving Ways, Detecting Ways, Essence's Perceptions, Unbarring Ways, Invisible Ways, etc etc.
Lists that can mimic the effects of skills, often with better results than the "real" skills themselves.
Imho these spell lists should be rethinked, or the effectivness of mundane skills should be increased: a master thief with 30+ ranks in Hiding should be better at doing it than a mage with a few ranks in the skill and Invisibility.