In my opinion, if a player wants to do the same Snipe + Flee over and over again for every battle in the game, that's fine. They're only going to be taking away all the fun from themselves and boring themselves to death.
And if necessary, that exploit can be fixed too. Maybe something like "if all party members leave a certain radius of an enemy encounter, their health and armor could be restored to full", so as soon as Snipe + Guerrilla fails to one-shot an enemy, the snipe + flee tactic fails to work. That's just a possible example.
Everyone definition of fun doesn't follow the same guideline and 100% lonewolf clear is one of the hardest accomplishment in the game especially when you consider that it doesn't work against bosses, forcing you to change your entire skill set and plan when it's down to a 1 v 1.
Guerilla tactic is a legit strat in a real world to thin out a herd and win with lower number. Why wouldn't it be a legit strat in Divinity now that has a bunch of logic-based strat like using environment effect? Not everything is an exploit just because one side figured out how effective they can be. If it was not intended and indeed an exploit, Larian wouldn't remove that 1 source Point cost from Sneak which allowed the strat to work at every encounter.
