Recently I levelled a lowbie Gnome Hunter through the old world, he's in Northrend now but the experience got me thinking, particularly my time in Un'Goro crater.
First, watch this cinematic. It's from the Hearthstone expansion Journey to Un'Goro. It paints a picture of a savage, primal land infested by man eating plants, thunderous lizards and ferocious carnivorous Dinosaurs.
https://www.youtube.com/watch?v=MG3nb7Oam4k
And then look at this
https://www.youtube.com/watch?v=nQIovXvSBfM
That's how Un'Goro currently looks in game, a fetid green swamp. If you were a Hearthstone player who had never tried WoW and then logged in, levelled and got to Un'Goro for the very first time, then the gap between expectation and reality is staggering.
Un'Goro crater, because of the cinematic, exemplifies a problem affecting WoW right now, a problem which gets worse and more expansive as the game gets older.
We used to say that WoW's game engine aged well. And it did, it aged very well. But it STILL aged. It's gotten to the point that trips to the old world mean enduring graphics so out of date that they seriously distract from the experience. The low res textures, blocking doodads and trees that look more like the stones of the Giant's causeway than actual trees, all of these show that perhaps something must be done to future proof WoW.
I believe WoW's engine is now a barrier to entry for any prospective new players. Why play WoW when you can play something that looks like FF14 or TESO? Because it's a good and fun game, yes, but if you can't get past the initial barrier of it's aging engine you'll never play enough to find that out. Wildstar, failure of a game though it is, shows what an MMO with WoW's cartoony graphic style could look like in the modern era.
At some point, Blizzard may have to grasp the nettle and just rip out the existing engine and replace it with something more modern. We know they have such an engine, WoW rendered using the Overwatch ending would look incredible.
The alternative is continuous degradation and falling behind. At some point, yes, graphics do matter and WoW is rapidly approaching that point. The scale of the task does not diminish it's increasing necessity.