I am curious how it could be any simpler?
Does the source have an uninterrupted LOS?
Is the wall bordering a zone that is in range of the attack?
Resolve.
I understand how the rule stated in the FAQ is applied. That's not the problem here. The problem is it seems unintuitive given how attacks usually work. Intuitively, and according to the rules, you can only attack a target in a zone that is at a range listed for the attack (0 for melee, stated range for your ranged attack) AND to which you have line of sight. That usually involves one measurement: to the zone that contains the target. Walls aren't in zones so they are an exception with their own ruling. All that is fine. What gets weird is that a ranged attack with range limitation 1-X can target the same object that could also be targeted by a melee attack, which inherently has a range restriction of 0-0. Then one can argue that's fine because the wall isn't in a zone, it's on the border between zones that are at range 0 and range 1. Ok, that's still fine. Then what gets weird is I can use a range 1-X attack even if I don't have LoS to any objects at range 1 (or beyond). Attacking a wall can require 2 separate measurements: one for LoS to the wall, and another for range to a zone. Intuitively you might measure LoS and range to a zone the walls borders to determine if the attack is legal (as you would for any other type of target), but this is apparently wrong.
Flying is already an exception to this rule, but it makes sense thematically since it's easy to imagine the target might be range 1 (or further) vertically above the arena floor. For me at least, It's less easy to imagine attacking something that's closer than the minimum range measured horizontally parallel to the floor.
As somebody else suggested, think of walls as being at range 0.5. Melee attacks, then, have range 0-0.5. Ok, but to be consistent with the current rules about walls that block LoS, ranged weapons that say range 1-X actually have a range of 0.5-X. That seems odd since the stated ranged of melee and "range 1-X" attacks don't seem to overlap... but with walls (and flying creatures) they do.
I don't have a gripe against the current rule. It's easy to follow. A bigger problem is that it isn't terribly easy for new players to find because new players tend to check the core set rules first, then maybe check the Codex as a reference (especially for key words), but probably don't check the more extensive FAQ unless there's an ambiguous case. From the rules and codex, it would at first seem that a range 1-X attack cannot target an LoS-blocking wall. This a new player may not bother to check the FAQ to find the current correct ruling. Perhaps the targeting rule for walls should be made more clear in the rules to prevent new players from missing it. Perhaps adding the following statement would be sufficient:
"If an attack has LoS to a wall and has range (but not necessarily LoS) to either zone the wall borders, then it can make an attack against that wall."
