The GF3 does not require AGP Pro. The only card on the market that needs more power than the slot can provide is the Voodoo 5 5000. However, this uses an extra power connector like a hard disk, and still does not require AGP Pro.
I guess if any 3D gaming cards come onto the market that need the extra power, then manufacturers will use power connectors like this until everyone has AGP Pro slot, or at least they'll provide a version that uses this.
The only cards that use AGP Pro are mega-powerful professional cards which can display on 4000 monitors simultaineously and render the entire Toy Story movie in 4.3 seconds (I may be exagerating slightly).
Now why can't the Voodoo 5 do this?
~ I know the human being and fish can coexist peacefully ~