If you can get some seat assignments with windows and aisles together (no middle seats) then if the gate agent is unable to assist you (and I do see GAs trying to help folks most of the time but often I hear them suggest swapping with others), then you at least have something worthwhile to trade with others, especially if they have a middle seat. I will swap window for window/aisle, aisle for window/aisle - but I do not care how much the person gets upset with me I will not swap to a middle seat but do not sit in their seat before asking them (that is rude).

Also, if you have window and aisle seats it will make it easier for the GA to do the swaps as they are "upgrading" the middle set passenger.

Hopefully the flight is not too full and the GAs can make the switches for you.