Is Rapid Casting a New Support or Replacing Arcane Tempo Support?

In the showcase video. Rapid Casting I, II and III were showcased.

Rapid Casting I gives 15% Increased Cast Speed
Rapid Casting II gives 20% Increased Cast Speed
Rapid Casting III gives 10% Increased Cast speed per each different spell you've cast in the last 8 seconds.

Arcane Tempo in 0.2.0 gives 20% MORE cast speed.

If rapid casting is replacing arcane tempo this is a massive nerf to any build using arcane surge, or that has cast speed investment on gear or the tree.

This support change alone goes a long way to cancel out much of the buffs done to the spell gems themselves.

They mentioned that they changed many of the support gems' names.

It was mentioned in the patch notes that they added 11 new support gems. Is rapid casting one of them?

i imagine a lot of gems were changed like that because they removed the limit. if we had the old MORE CS/AS then this gem would be linked in all skills. i image the same will be done to the general 'more damage' supports