Thanks for this good question!
The purpose of the first map parameter is to be overwritten by a subclass and also if you have many if clauses you sometimes want to improve the priority but not in some really ugly cases like for tunnels. And so the order of the if clauses is less relevant and makes overall usage a bit simpler.
But here I’m open to any better system.
In general tuning the priority can be tricky and problems can have several reasons. You’ll have to look into every edge if it gets the intended priority after import.
Also the aim of the next release will be to make it easier to create custom vehicles/weightings.