I'm obviously way too late in this thread to fully contribute, but my preference is that a game should generally not allow someone who scours the rules for edge cases to get an advantage that isn't obvious and intended. I'm fine with system mastery (e.g., you know that against an enemy with high AC, don't use Sharpshooter, but the feat is good against someone with some sort of damage resistance), but I very much disliked 3rd edition and Pathfinder's style of "Okay, let me get +1 AC from this item, that feat, this synergy, that item, this other item, and this contentious reading of a conditional effect of this third item."
Like, a well-designed game lets you as a player accomplish what you want. If I want to make a character who is good at archery, it should be clear how to do that. That might require giving up some other skills or powers, and there should ideally be a couple options that are better in one circumstance or another (maybe you fire poison arrows that are good vs. animals, or you fire radiant arrows that are good vs. undead, or you are better at skirmishing through combat, or are better at sniping from afar), but once you decide what type of character you want, there shouldn't be tricks or dead ends that sound good but are actually bad.
For example, in 3e it was discovered that you were often better off making tons of attacks with a pair of light weapons and stacking damage bonuses, rather than using a single big weapon. The game should make it clear whether big slow weapon or small fast weapons deals more damage, and make the choice meaningful.