Comparing the other Start Collecting boxes, it tends to be 3 other boxes. There a couple with 4, but that's really because of a clampack hero, rather than a big kit.
With that in mind, I'd say General on Griffon, Pistoliers. Then next is tricky. As they have a choice between State Troops, Handgunners and Greatswords. They could be awesome and revive the 20 man militia box.
All of the start collecting boxes have all the full contents of the boxes they are separately, so state troops would have all the weapon options.
Unfortunately, I don't foresee a Freeguild Start Collecting box any time soon, but then again, there's not really much in the rumour pipeline for AoS anyway. We know Disciples of Tzeentch are coming this month, but nothing really much beyond that.