Unfortunately I don't know what you mean by 'starts to miss and humps'. I would have thought that if one of the clutches is worn out in the gearbox then as you accelerate quickly the revs will rise, but your speed will not. There is a condition that I have read about that was called 'flaring' where the gearbox does not change gear properly and the revs rise during the gear change. Could it be this that you are describing?
On my car, if I reactivate cruise control when the speed has dropped well below the set speed, the car will accelerate harshly, changing down gears sometimes, in order to get back to the set speed as soon as possible. To avoid this I always use the accelerator pedal to return my speed gently until I am at the cruise control speed, and then reactivate it.
Also have you ever had the gearbox oil changed. I would certainly try that first if it is the original oil.