To be honest Jim I don't think this installment was cynical enough.
From my long experience with video games and watching the industry it seems to me that "fun" is tossed around when a game developer can't think of any other way to justify something they are doing. "We did it this way because we think it's more fun" oftentimes comes about as a way of trying to justify why they couldn't produce the innovations that were promised.
To use an example, look back at the old MMO "Age Of Conan" (which is still running) it made a number of lofty promises, most of which were achievable within then-current technology, but delivered on very few of them. Some of their promises like having formation-based PVP fighting, a system in which instead of running around and trying to circle strafe each other as a DPS lonewolf or semi-invulnerable self healer, you would have to get into position with other players and actually coordinate like an actual military action in order to succeed. The idea was to even have specialized characters like pikemen who were going to specialize in formation based PVP combat. Needless to say Funcom dropped this idea which a lot of people were looking for, and actually pretty late in the dev process after it had been hyped seriously, their justification was "it wasn't fun" and instead they pretty much delivered the same kind of MMORPG PVP experience that everyone else had with things at best being loosely coordinated pre-made teams of lone wolves, as opposed to everyone having to form up and coordinate in formations, or mages combine powers in rituals to achieve bigger effects and so on. At the end of the day "fun" was used as an excuse for "we just really can't deliver this". To some extent you also see this in their "The Secret World" product where their much lauded totally free-form "play anything you want" character system is actually highly regimented as only very specific things tend to work together, you have to unlock powers in a specific order, and your given a pretty tight limit on how many abilities you can have active at one time. All of which makes sense from a game design perspective, but at the same time isn't what they promised, and again was justified as being in the name of "fun".
To bring this around to the example put forth in "The Jimquisition", it seems to me that "Grand Theft Auto V" is largely using "fun" as a justification for not having innovated much and having pretty much stole wholesale from other games. That's in of itself not a bad thing, I agree that innovation for the sake of innovation generally doesn't work out. However in the clips I've seen of "Grand Theft Auto V" I see a lot of cover based shooting, with "blind firing" options present in some other games, combined with things like underwater swimming (which a lot of games have), and base jumping with parachutes and such which is something that was mastered to an extreme degree in titles like "Just Cause 2". To be fair all of these things can be great fun, but when I see a company parroting "fun, fun, fun" while pretty much trotting out a checklist of things you'd more or less expect nowadays, it makes me quite cynical, it seems "we did it because it's fun" is the claim because really they couldn't find any other way to justify it. It would be like "Call of Duty" using "fun" as a justification for it's painful stagnation, along with all the other "follow the leader" shooters trying to pretend they are "Call Of Duty".
Speaking entirely for myself, I haven't been all that impressed by the new "Grand Theft Auto", sure it's the prettiest one in the series, but it seems pretty derivative to me. Nothing there really impresses me the way CJ rocketing around with a jet pack did in "San Andreas", largely because that was pretty new and fresh at the time, you toss a Jet Pack in now it's nothing special because well... we've already seen that, and it's actually a step backwards to not have crap like that which people have been trying to drill into Rockstar's head for a while now. I guess it doesn't have to be innovative to be good, but at the same time I look at it and can't help but wonder what is supposed to make this one stand out from other sandbox mission & mayhem games other than the high quality of the graphics (which you expect, due to it being the latest one out).