Ok, I'm going to dissect each individual part of your most recent argument. I really have nothing better to do right now so...
2. Skill checks in dialogue doesn't count as gameplay, it counts as dialogue.
Technically it counts as dialogue, however it encourages you to take ranks in things like Speech and Science, which are not immediately helpful in combat. It allows you to risk some of your combat build in order to become more of a specialized character with other means of solving problems.
3. Nah, pretty sure the absolute god-awful engine from 1999 is pretty bad.
While the very original one from Fallout 1 was somewhat poor, that makes sense since it was the first installment of the series. And if you've ever played Fallout 2, you'll see that it improved upon all the problems of the engine, and made it very playable.
Fallout 2s engine is, IMO a brilliant engine for an Isometric RPG that consistently challenges you and gets you to use strategy to try and adapt around new challenges.
Let's compare this to Starlight Drive-In from Fallout 4. There you can find a Fusion Core, a few Bottles of Nuka Cola and some Mole Rats.
The only difference between Fallout 4 and Fallout New Vegas' Drive-in is that New Vegas' one occasionaly has Scorpions and Ghouls pass through it, whereas Fallout 4s is a permanent den for Mole-Rats. And surely you would argue that having the occasional monster pass through is somewhat more realistic?
What do you expect to see from an abandoned Gas Station?, I know that Bethesda would have probably put some Ghouls or Supermutants in there, but lets face it, they have better places to put there lairs then abbandoned Gas Stations.
I'll give you the benefit of the doubt here, since it was mentioned to be home to Mayor Steyn of Nipton's secret stash, so I guess they could have put a very well hidden stash of hundreds of bottlecaps, or drugs or something, but apart from that, what else can you do with a gas station?
The NCR are using it as a base from outside of Freeside. Doesn't sound completely useless to me.
http://fallout.wikia.com/wiki/East_Pump_Station <- Nearly empty, except for a quest objective/start
http://fallout.wikia.com/wiki/NCR_Sharecropper_Farms <- Good setting, nothing in them but a quest start.
A. These act as a place where the NCR get there Food/Water from. They are there for a world-building point of view.
B. The vast majority of Bethesda settlements are soley there for the sake of 1 quest before they become Yourz 4Ever. Single Quest settlements however, are incredibly rare in Obsidian games, as most are fleshed out enough to have dozens.
A Cave with a bunch of Nightstalkers and a Nightstalker Boss Battle. A series of Monsters and a Mini-boss?, Sounds awfully like a dungeon to me.
What more do you want from a dungeon?, Phat Loot?, Cause animals aren't going to have much loot.
No Shit, it's a place called "Coyote Den", the whole point of it, is that it's a den of Coyotes. Since you usually see Coyotes running around hunting, it makes a nice change of scenery to see where there actual den is.
Houses that have been flooded over the years. That's quite an impressive piece of world building right there, to say that there are Old, Ruined Houses which were built before river levels got that high. And besides, there's a nest of Lakelurks, so people looking to shoot shit can fight something.
The Main Fire Gecko lair in the whole Mojave.
And I don't see why you are complaining about this one. This one is literally a dungeon. It has minions(Fire Geckos) for you to fight, a Boss Battle(Legendary Fire Gecko) and a very expensive/powerful weapon as loot(Fat Man Launcher). This is literally as close as you can get to being a dungeon, while still maintaining it's an animal lair.
Scorpions and two stashes of caps. What more do you expect to see from an Airport, which was only recently abandoned by NCR troopers.
No shit. The Vast majority of caves you see are going to either be A. Empty or B. Animal lairs. You know why?, Because that's what caves are like in the real world.
And besides, you are somewhat rewarded for exploring this cave, as you can find a suit of combat armor in an earlier victim's duffle bag if you explore long enough.
A. This seems to have formerly been a stash of some kind before it was taken over by Nightstalkers.
B. This is literally a dungeon. You go in, and you find a key to a nearby door, which you would otherwise have to lockpick, you walk through lots of mobs such as Nightstalkers, you fight a Boss battle(Legendary Nightstalker), and there is a stash with money/weapons. Oh and guess what, there are traps in the stash.
You literally have Traps, Mobs, Bosses, and Loot. What more do you want from a dungeon?
Precisely. It's there for an awesome quest. You have no grounds to complain for this one.
http://fallout.wikia.com/wiki/Devil's_Throat <- Hole with Super Mutants for some reason.
A crater filled with Centaurs. There is a Giant Centaur there which can act as a form of mini-boss. You get a unique set of Combat Armor and a Minigun upon completion. This is basically a dungeon!, Next!
So you're telling me that swimming underwater and finding a huge cave isn't enough of a reward as it is. Not all exploration has to be about Loot and Monsters.
Not every place has to be interesting. Realistic Worldbuilding means you are bound to find a lot of shacks.
A cave with rats and unique weapons. Not uninteresting at all.
I think you get the picture by now.
Also, the great mod count is pretty huge, we have the NVBounties, Project Brazil, DUST, DLC reworks, Millenia's guns <3, AWOP, Coito ergo sum, TTW... Can you say somethong about that, 
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