I think the fight seems scarier than it is with all the summons. And it's its best feature. It keeps pressure on the player, which is what a boss fight should be. In comparison, the boss fights in the goblin camp are too straightforward and would be much better if some surprise mechanics were involved (once you understand the potential drum call, it's just rinse and repeat)
The githyanki raiders give a tuff fight too. They strike hard and are very mobile. I have some good hope for a challenging tactical mode in the future.
They are going to add a difficulty level so at it's highest levels I imagine there will be some significant challenges. BG2 and NWN had easy modes where aoes were enemy only, higher difficulties increased armor class and hp of mobs, potentially more mobs and the like.
