As Mike points out, the 3" GG isn't the best tool for serious correction. You'd be better off with a 3" BP on a PC or similar DA.
That's a good recommendation and here's an article with lots of pictures to show different variatons...
3.5" Backing Plates and 4" Spot Repair Pads on DA Polishers
Here's what the 3.5" backing plates look like mounted to DA Polishers with 4" pads, including CCS, Hydro-Tech and Surbuf and also I've included what the 3" Griot's Polishing Pad looks like for size comparison using the adapter and the rotary buffer backing plate to attach to a DA Polisher.
Pictured are the PC, GG and Megs DA style polishers... (Love this new cart)
I had a 3" Metabo 400SXE which was about the same tool as the v1 GG 3", pretty anemic. I used it mostly clamped between my knees pad-up to polish small shiny bits. Once I picked up the 3" GG I peddled the Metabo.
YMMV... TL
I'll back everything you wrote... I have a Metabo 400SXE and I hoped it would work great but it's pretty anemic. Like the version 1 Griot's Garage 3" Mini Polisher it is unable to effectively keep a pad rotating under pressure which means
neither can be used to remove paint thus neither can be used to remove defects out of paint.
The newer version 2 of the Griot's Garage does a better job of keeping a pad rotating under pressure but it's still not as effective as using a spot repair pad on a full size DA polisher or even a rotary like you see here,
Pictures + Video of 1932 Ford Highboy Extreme Makeover
The Flex 3403 with a Griot's Garage 3" Polishing pad comes in so handy for working on thin panels and there were plenty of thin panels on this car to buff out.
The new version 3" GG Mini Polisher can remove defects but you have to use exact technique with it. Keep in mind not everyone is always trying to remove swirls and scratches, some people just want to machine apply wax or paint sealant to tight areas or do some light paint cleaning and polishing.