Nah, he would notice a major problem if his css file didnt load. I believe he's taking to the extra space that was caused by the "last post by". And, the space isn't a big deal at all and definently worth the new feature.
I've gotten completely used to the forum spacing already, just give it a few days!
Also, about the lines. If you would have seen the forums without the lines, you would have flipped. All the dates and last posts ran together, it was a nightmare. The line is a GOOD, GOOD thing.