Actually, he is right. Most of the hydras, even the ones which are supposed to be able to swim, do not have a listed swim speed. This issue come up for my group last weekend. The DM simply made an on the spot call (and rightfully so) that the hydra we were fighting had a swim speed of what...
Without a house rule, they have no choice in whether or not they do it in 4E. By RAW and RAI (as clarified by a few WoTC articles,) it is perfectly viable to have a creature attack themselves with powers which allow you to choose the target for the creature's attacks (of which dominate would be...
How do you have a proficiency with your unarmed strike without being a monk or a brawling fighter? Unarmed Strike tends to do less damage than a weapon.
Also, you actually can throw your unarmed strike with the right feats or items.
I like to use Apocolyptica for ambient music.
Clutch is good depending on what kind of game you are playing and what kind of feel you want.
YouTube - Clutch - "Electric Worry" DRT Entertainment
I do not think Lolth is as tough as many people seem to think. Someone with the Lord of Fate destiny would make 4E Lolth cry as she spends the majority of the encounter dominated.
Overall, I think the monsters in the book are nice. Having a little more fluff is nice. I know many people...