I adjusted the battle map a bit. It originally included a runic circle that served as a nonsensical power-up. I turned that into a ritual site where the wyrmpriest triggered an effect: six kobold heads lit by internal flames floated into the air around the circle (not very far up - about waist high on a kobold). Each of these allowed a kobold the use of a breath weapon (+5 vs reflex, close blast 3, 1d8+2 damage, 1/2 damage on a miss) before it burnt up into skully ash. This effect could have been countered with Arcana or Religion, but no one tried (and Bloodaxe decided to counter it with his hammer after the fight). I also decided that part of the river on the map had a heavy current that could push creatures downstream, but no one went into the river... so... ::shrug::
Anyway, they killed the kobolds outside and went into the lair - which I had also toned down. I made Irontooth a 2nd level elite brute - he dropped about 20 hit points and I reduced his extra damage when bloodied to 1d6. He still took a while to take down (in part because people kept missing him at first), but the PCs all made it. There were plenty of times when they were hurting, though.
- I think 4e makes balancing encounters to a party's ability pretty easy - I wanted the fight with Irontooth to be close, and I think it was.
- Kobolds make really effective snipers. Their shifty ability lets them pop in and out of total cover while taking a shot.
- Combat in 4e is simpler to run. I wouldn't want to run a combat in 3.5 with 10 different monsters using 5 different stat blocks. I did this last night with rules I wasn't nearly as familiar with... and I didn't have any problems. Also, rules look-ups were minimal despite this being only the second time we've played.
- Combat in 4e isn't any shorter than in 3.5, but more happens in the same amount of time. The PCs are fighting more monsters who have more hit points. Rounds go quicker, though there are more of them.
- Flaming sphere is badass.