I dont get the rant about hybrids, while actually footmage/dexmage are the ones being screwed with the new scaling. A well rounded tindremere hybrid will effectively hit as strong as a dexmage und just run a little slower while being able to wield weapons efficiently and wearing better armor. Sure the dexmage probably will have more mana and a little more magic defense but will this be enough of an argument to chose dex over hybrid?
The main reason to pick the mage over the hybrid would be for the extra mana, and active skill points so you could dabble in multiple magic schools when they are released. Most hybrids will be relegated to one magic school unless they invest very little into a few.