Well, as a retired (30 years) OSHA Compliance Officer I agree with you that there does exist a bit of leeway in the forklift "training" standard but it does outline the subject matter which needs to be covered and as for the time requirements I would like to point out the following section:

1910.178(l)(4)(iii)
An evaluation of each powered industrial truck operator's performance shall be conducted at least once every three years.

I know back in the days when I was conducting inspections, I would look for that 3 year update on inspections. I know it states "evaluation", but a good refresher training course every 3 years is what we wanted to see.

Good luck