Not all factions have many cards that fit the siege description so I think that combining the ranged rows makes perfect sense.
I think this is a reasonable point, from a tactical perspective. Technically, Northern Realms and Nilfgaard are the only factions who use proper siege engines. Skellige's ships are not true machines in the traditional sense (and never mind that they require a navigable shoreline or rivers to attack or support land troops. . . ); Scoia'tael's tactics are not developed for siege warfare (although I suppose dwarves could employ engines of some kind); nor do the majority of Monsters construct this sort of advanced equipment. Stretching the definition of a siege unit to a large, rather unwieldy 'tank', some giant creatures and dragons could potentially qualify, but I've always thought this a bit much. Overall, there are only a few units which would 'realistically' require the distance of a siege row, if we consider the board as a battlefield. Most units could get along fairly well at closer quarters.
A few grand machines need to be set far back on the battlefield for defence purposes. Trebuchets, for example, must be constructed in place for a siege, preferably well behind the front lines, out of shot of the walls, so their crews may work in safety, and cannot be easily repositioned. Basically, they are static heavy-artillery pieces, which are best suited for long-range assaults on castles or troops. (They're not so good for pitched battles, and nearly worthless for guerilla fighting). Additionally, their operation is rather slow. Ballistiae, and some catapults, are another matter, since these can be mobile, anti-personnel weapons. While they do not need as much room as trebuchets, they do require distance in order to be operated in security. One of the points -- to name only one -- which Gwent has hitherto overlooked is the fact that real siege engines can be captured or destroyed if placed too near the enemy's troops. There are many other tactical and practical military considerations which have been suspended for the sake of the game's style and format, of course.
I'll be curious to see whether Homecoming's two-row system introduces a bit more 'realism'. . . .
