You are correct. It looks like Explosive Shot and Black Arrow came into existence for WotLK. It was more of an over time transition than I remembered. I think the MoP changes forced them to really start paying attention to spec identity though, since that is when specs essentially became individual classes. And when they reached that point and started seeing a spec called Survival and looking at the foundations of its background, having abilities like Explosive Shot and Lock n Load didn’t make much sense.
Purely speculation, but I would wager MoP was just focused on completion of the transition into the new spec and talent system itself, and WoD is when they started seeing this glaring identity crisis in RSV.
I do understand that the original Survival tree offered improvements to your melee potential as something to fall back on when targets closed distance as opposed to promoting melee as the core of your assault, but I imagine at a time when nailing down spec identity was paramount (leading into Legion with spec specific Artifacts being THE feature) they felt that emphasis on improved melee was a stronger base to build on than blowing up the forest.
My biggest issue is that they kept the use of explosives. If they had replaced the explosives with something like Snake Trap or strictly Pheromone Bomb, I think it would have been a much more fitting transition. Instead, they wound up pissing off a bunch of players and left themselves very little room to rationalize it.
I brought the conversation here since we were getting so far off topic of that thread and right on point with the purpose of this one.