And another thing (inspired by Jabawocky's comment):
My sister works at KLM, about the same time as you spent with yours now. She never complained about not being able to pick routes.
Their system, as far as I can tell, is the same for everyone. If don't put in a request and take the package of flights assigned to you, you accumulate points. When you put in a request for a package, the one with the most points gets it and points are deducted.
So with a holiday coming up, she does a few three-sectors-a-day Europe weeks as assigned, then puts in for the "fly to KL, spend 4 days on the beach, fly home and get 6 days off" so she ads another week to her holiday. Almost guaranteed to get it.
She's been doing this since the day she was hired.
So yeah: there is another way and it is up to YOU to change it, the senior crew that calls the shots in the union have no benefit from making that change.