I agree that larger driver size doesn’t give improved performance.
When it comes to golf equipment technology I turn a blind eye to the hype of the manufacturers and their golf media acolytes, and look at what the pros are doing with the technology.
If the technology presents a valid performance improvement, the pros will use it, because it represents money in their pocket.
Everything I’ve read indicates that none of the pros use a 460 driver. Even when they endorse a certain model 460 driver and put it in their bag, the manufacturer makes a special “modified” version for them to actually use with a smaller head, along with other “modifications”.
I have been an advocate for a more moderate sized driver head for years. I currently use a Callaway Optiforce 440cc, and a Callaway Bertha Mini-Driver (12°). The Optiforce is 44″ and the Mini is 43.5″.
The Mini is easier to hit, but the Optiforce goes further (just not as straight). I would like to see something in the middle, around 400cc as you suggest, with the Callaway driver technology. It would lack a little of the MOI, but would be easier to make lighter. It would be a great older golfer driver.
franklygolf 
I agree that larger driver size doesn’t give improved performance.
When it comes to golf equipment technology I turn a blind eye to the hype of the manufacturers and their golf media acolytes, and look at what the pros are doing with the technology.
If the technology presents a valid performance improvement, the pros will use it, because it represents money in their pocket.
Everything I’ve read indicates that none of the pros use a 460 driver. Even when they endorse a certain model 460 driver and put it in their bag, the manufacturer makes a special “modified” version for them to actually use with a smaller head, along with other “modifications”.
I have been an advocate for a more moderate sized driver head for years. I currently use a Callaway Optiforce 440cc, and a Callaway Bertha Mini-Driver (12°). The Optiforce is 44″ and the Mini is 43.5″.
The Mini is easier to hit, but the Optiforce goes further (just not as straight). I would like to see something in the middle, around 400cc as you suggest, with the Callaway driver technology. It would lack a little of the MOI, but would be easier to make lighter. It would be a great older golfer driver.