I travel through a lot of different airlines, and each airline has their own boarding strategy. I have a rough estimate of what boarding group I will get with the seat I pick.
It would be nice to have the boarding group # displayed when selecting your seat # on the different airline sites. Also, it would be nice to display the number of tickets seats purchased with priority boarding. This way I would know when to pack lighter for a smaller carry on, or at least expect to check my luggage in to pick a seat with an earlier boarding assignment.
Different carriers have different number of boarding groups and strategies. United has 4 groups and board by outside-in, 1 status, 2 window, 3 middle, 4 aisle seats. Other carriers do back-to-front (4 groups), while others even do a reverse pyramid strategy (usually more than 4 groups).
Back window seat will guarantee you at least a boarding group 2, B, if you are status-less on most airlines and have no clue of the airline boarding strategy. Guaranteed luggage in overhead, except maybe United since the majority is group 1, which is a different story.