The objective should be to make the raids take the same time than the rest, this will discourage the ilvl cheese.
Making iLvl more strict and/or redesigning some fights should do the trick.

As far as new players go... dunno, I'm against singelplayerizing the mmo too much. It took me a while to get over my fear of doing raids, but I really like it now.

One of the things I liked about Aglaia's first days was that it was hard enough to make half the raid constantly die, but easy enough that the more experienced half could drag the others kicking and screaming to the finish line. Perfect tuning if you ask me, lol.