I can only agree to 50% of this statement.
First I want to keep gameplay and anything, which has nothing to do with graphical fidelity, out of this discussion, except for the single statement that good graphics won’t save a bad game, but will improve a good game.
Now onto the main point of my post:
Global illumination can change the look and feel of the game quite drastically, depending on the situations given within the game. Of course it has to be accompanied by an overall quality environment, otherwise it’s just wasted resources.
In quite a lot of cases GI can be quite important. The project I work on has a ToD-system and a lot of dynamic environments, so Lightmass is utterly useless in this case. The SkyLight solution works only sub-par, simply because of how it works. Especially indoor areas look just weird, since Skylighting doesn’t provide anything close to proper GI. The differences between no GI and with GI are quite noticeable (we use VXGI), even for the untrained eye. Sadly I don’t have access to the project right now (PC had to be setup from scratch), but I have some old comparisons lying around (they use default settings if I’m not mistaken and were shot with an old VXGI version, so no multi-bounce as well):
http://i.imgur.com/n8HkHoVl.png
http://i.imgur.com/UPOQaXgl.png
The difference is quite obvious and I wouldn’t brush it off just like that.
Also: simply saying “It’s never the tools, it’s the person using them.” is ignorant and shows a lack of understanding of the opposing site, even worse considering your statement can be taken as personal offence.
We are talking about solid limitations of the engine, not some incapability of a person, team or whatever. UE4 currently can’t provide convincing fully dynamic real-time GI. The solutions we are provided with by Epic are limited and don’t fulfill the needs of some (if not many) projects in an acceptable manner. It’s not mandatory to have this kind of GI, hell no, but for the projects that strive for realistic graphics, it can change a lot.