Skulking: Its sole consequence is to make play longer and more tedious as the attacker waits patiently for the defender to do the obligatory shuffle that we all know is coming, but is acceptable because play testers used it too and therefore it’s “built in” to the scenario.
All of that said, skulking is nothing more than a consequence of the turn structure that was later rationalized as “modelling” a defender’s dynamic use of terrain. That’s a stretch, but so is slapping a hex grid across the world’s surface.
Anyway, the real problem is THE ADVANCE PHASE itself. If we remove the advance phase from the sequence of play and just allow GO infantry – who move only one hex – to enter an enemy hex during movement then we eliminate skulking (and other issues) while also making the game play faster with more historicity.
Why the added historicity? Because the advance phase violates a fundamental maxim of military operations – movement draws fire. That does not hold, and is in fact impossible, during the advance phase; a defender can move in the open without suffering consequences.
From the original Squad Leader design notes, you may recall that the advance phase was created for the express purpose of simulating the cautious approach of attackers during a close assault. Therefore, when ASL added “assault movement” and broke the old “-2 for moving in open” modifier into FFNAM and FFMO it mitigated the need for an advance phase altogether. One can now use ASL rules to simulate a cautious advance during the movement phase and therefore there is no further need for a phase designed for that purpose.
Yes, of course, dropping a phase would have a huge impact on all existing scenarios. But after decades of play it’s no surprise that we have found flaws in the system. I can certainly live with those flaws, but I could also live with “ASL II” that delivered various improvements such as dropping the advance phase, making all counters 5/8, removing crews, etc. We all know there would be no shortage of new scenarios for any and all interpretations of SL.