I think it might be more of a winter maintenance thing. Like they wouldn't have enough time/man power to work on all the trains between candy lane and the opening of the park. They jump on what's closed for the season now and then work on what's still running later. Two years ago when I first went to Candy lane was the first year they had coasters open and Wildcat only had 1 train. I asked a ride op the reason for 1 train and they said the other train was getting the winter maintenance started. One train operation was pretty brutal as far as waiting.
Id like to see Great Bear, Comet and Lightning Racers open. They are all in areas of the park that are open for the event, but at that point it be like a fully operational park besides the Intamin coasters