Looking forward to all of the S3 item changes to be honest. Sightstone is going to be FAAAAAABULOUS! I can't wait to see all the item changes together though (the patch today was pretty disappointing in terms of the changes it have.) It's always good to shake up the game a bit to keep things fresh.
Would definitely consider LeBlanc to be a combo mage too. Even with a negatron, LB still hurts heck of a lot >_<; but to be honest not every champion needs a late game. Some are just designed to burst early and win early before it's too late. LB is one of those high risk, high reward if you can snowball early enough and better win by 30 minutes.