Yet the reason for that is probably the (relatively) small model count that you have in tabletop Warhammer battles. If ranged units were too powerful, the games would end in a couple of turns, even before they reached melee range. But in TW the battles are larger (so units are more expendable), allowing for more powerful ranged units. Of course big/powerful units should be more durable, I would not like my badass Ogre or Dragon to be killed by a couple of arrows, but when it comes to normal troops, I think ranged fire whould feel powerful enough, and not just a small annoyance that can be perfectly ignored.
That said I'm all in for extreme asymetry when it comes to this kind of rules. For instance, I'd want a volley of arrows shot by good archers to heavily decimate a band of goblins or human soldiers, for instance, but do absolutelly 0 damage to a steam tank or reduced damage to a big creature (or just give big creatures more hitpoints to compensate).
Well, let's see what they come up with. Warhammer lore, as far as I'm concerned, is developed to allow or make feasible all kind of engagements between all the different factions, so it's in some way a "battle sandbox". I think something can be done to create a sandbox strategy game, even if some stuff has to be reimagined (a task that Games Workshop carry out themselves constantly, so I don't see the problem). I'm curious about how CA will deal with this.It's quality vs quantity. Replayability can be achieved in a narrative driven campaign if it's a non-linear one. The Total War sandbox just wouldn't work for Warhammer.
There are examples of Warhammer games made into sandboxes to some extent with a decent success (For instance, the campaigns in Dawn of War (the one with the Tau), where you get a "Risk" board, which far from having the management complexity of TW (least Paradox Games) still allows for a basic sandbox gameplay, letting you create your own narrative as you conquer (or lose) provinces.
Something so basic would definatelly be a disappointment given what I expect from a TW game, but proves that a sandbox game can be achieved to some extent in the Warhammer Universe.
Remember that Warhammer is a battle game first and foremost, a business developed around selling miniatures and playing tabletop matches. Battles don't adapt to lore, it's lore the one that adapts to battles.