If you don't need support then it's irrelevant if you're racing or training. There are plenty of people who train in flat, lightweight shoes.
I'm with you. I'm all for the minimal shoe. The problem is that as a relative beginner I went from Gel Nimbus 11s to a lightweight racing shoe, the Saucony A3 . After running in them for three weeks I discovered plantar fasciitis and knee pain. I'd never heard of PF before. My own fault obviously, but they felt fine for the first 4-5 runs. I didn't realise the pain was caused by the shoes and I thought it would go away like my other aches. It didn't.
So I'm approaching the move to minimal shoes in a different way. I'm progressing to a slightly lighter shoes every six months as I replace my old pair. The Nimbus was 375g, my New Balance 759s are 320g. I think the jump to 250g K-Swiss Ona's will have to wait a bit.
Anyone know of faster ways to strengthen my feet for minimal shoes?