While the over all quality of a work can be and often is subjective, the amount of influence it has throughout media and pop culture is estimatable if not exactly quantifiable.
You talk like Yoda, people know what you're doing. You make a Darth Vader breathing noise, people know what you're doing. You make light saber sounds, people know what you're doing. You tell someone that you're their father, people know what you're doing.
If someone says they've never played Mass Effect, they'll get a shrug and someone will say "you should play it, it's really good." Someone says they've never seen Star Wars, people will stare blankly and wonder at how that's possible.
There are people, in real life, who hold the Force to be their religion.
Mass Effect doesn't have that level of cultural prominence. That isn't opinion; that's objective fact.
I love Mass Effect. I really do. It's one of my favorite series of all time. I'm not deriding it or dismissing it when I say that it simply has not had the cultural impact of Star Wars nor has it had the impact on the gaming industry that Star Wars had on the film industry.
That isn't saying it hasn't had any impact at all. It's had quite a bit of impact, though it's hard to say how much of that impact is directly attributable to Mass Effect and how much can be attributed to Bioware's style in general. But it isn't an exaggeration to say that Star Wars fundamentally changed the way movies were made; Mass Effect didn't fundamentally changed the way games are made.
I understand that all, and I definitely agree about Star Wars in general having more impact.
I think though Mass Effect is well on the way to be on that track. All it kind of needs at this point is time to incubate it.
Where I differ is I do feel we have seen Mass Effects "style" kind of change things. Fallout 4 is pretty emblematic to it in some ways; the voiced protagonist, the wheel of dialogue, the cinematic experience being pushed as a new way to play the game, the hybridization of role-play elements to other genres and actually working properly. We also have save imports and the evolution of their use and design, while heavily touted by BioWare as a major feature, are used in varying degrees in other games as well.
We see a ton of games taking bits and pieces of this into their design basically. I get why people say Halo is a big deal for FPS's in general, it practically revived FPS's by making it popular through lan and online play on consoles, much how Goldeneye 64 was the Multiplayer experience people flocked to before it. Yet, CoD reinvented the wheel in how they did multiplayer online FPS by borrowing role-playing elements to mix things up. GTA really pushed the boundaries of an open world while Bethesda keeps improving on that, Minecraft is emblematic of the social aspect of gaming and creativity, and every indie under the sun has emulated that formula in some form.
Yet through all that, we see Mass Effect reaching around them all bit by bit. Telltale games, Bethesda, and CD Projekt Red have used elements found in Mass Effect to push their own products, nothing wrong with that either, but it is noticeable and I would argue very impactful for the future of gaming, let alone RPGs. BioWare has also taken from other sources to improve their own games too; the dialogue system has seen a lot of changes based on feedback as an example. The keep in Dragon Age is probably the best solution to solving the issue of save-imports that we have. It's constant evolution of the mechanics and design that helps to keep it relevant too, and if it is successful, then others will follow suit.