I want to store only request threshold in logistic group and dynamically change it when upgrade trains. But also I use different request priorities and i have to use different groups per different priority and threshold. Instead of that you can unpin priority field from logistic group. So i could have only 2 groups - for cargo trains and fluid trains.

It's an interesting suggestion. I'm not sure I can think of a proper way to implement it though, without introducing things that can go wrong when copying/blueprinting combinators.