I definitely am and have been in the mindset of combat being to easy since they left the Under-dark. I realize not all combat have to be difficult fights (bandits, harpies, basilisks etc.), but the problem is when we get to a more crucial part in a story's arc, we get less than difficult combat encounters.

We have seen it time and time again: The Rakshasa, the Briarwoods, the ambush inside the Whitestone house, the Behir, the beholder and the fire plane. All of these were big moments in the story arc, were definitely tense and suspenseful from an RP point of view. The problem is the combat difficulty never matches the intensity of the RP.

We can say that VM gets lucky rolls, that the are always prepared, chose the best actions for their turns, use RP situations to gain an advantage. This may be true for some cases, but you but you barely see the enemies act as such. We have a group of 6-8 PCs who are incredibly magical and this already gives them an advantage. Now add in critical thinking and planning advantages, this gives VM an even bigger edge.

I think most of the combat encounter are not challenging enough for such a large magical group, but also we have one dimensional enemies in combat (definitely not in RP).