3 seasons comes appropriately to mind with the approach of autumn, but even at other times of the year, you find that boots made for this level of walking are usually best suited to be all rounders if you don't have the loot to kit yourself out with different boots for different grades of walking. 

What you're looking for is a boot with a reasonably stiff midsole flex - not totally rigid, but neither should it be so floppy you can bend the boot in half with hardly any effort. This kind of spring supports you nicely when you're yomping over rough terrain, and you won't notice any stones underfoot. 

Similarly, torsional stability in 3 season boots is more desirable, because it means you can scramble happily without tiring your feet, and you're less likely to feel a long day if you're backpacking. How can you judge torsional stiffness? Just grab the boot at both ends and twist in opposite directions. If you go half a revolution without even flexing your muscles, chuck the boot in the bin. It should actually be quite difficult to twist the boot, and certainly if you can get more than half an inch of movement, you need to be looking at something else. 

Weather resistance is something you need to consider more carefully. Fabric boots are great in hot dry weather, and they're not too desperate if you happen to get them wet in a sudden downpour. But unless they have a breathable waterproof membrane lining, the penetrating sogginess of upland peat bogs will have your feet craving for wellies.