After another 20 odd replies i could write reply 60 again here. After pondering over this for a few days, leaving the bikes in each class as it is already seems to be best answer. If the cost of buying a pre75 bike is to much for some then the oportunity to buy a cheaper pre78 bike came along Im sure they would jump at it. Pre 78 will grow for many reasons.
1-cost of bike
2-smaller class appeals to some as more chance to be closer to the front
3-better ride for older bodies
4-cost of parts to maintain bike
With the split of the nats could also be a bonus for pre78 as everyone loves more ride time, so maybe more bikes will find there way out of the garage as theres less classes they can ride. As this would create more interest in this class, interest creates more interest and so on. I hope time doesnt prove me wrong. What ever changes the powers to be make, Im shore not everyone will be happy. What ever the rules, just get the bike out the shed and enjoy the ride along with the culture VMX is.