In regard to UE3, I think I would have liked to seen more developers using that over UE4.

Arkham Knight, Outlast 2 and Mortal Kombat 11 are actually some of the best looking games this gen and run at a high resolution. UE4 though, its really a mixed bag and has games running at 720p on a base X1. It seems to me UE3 would have been sufficient for numerous UE4 games, would have delivered comparable visuals with better resolutions and likely better load times.

The premium consoles do see significant improvments on premium consoles, but sometimes its just for 1080p like on the PS4 Pro. There are exceptions though, I consider Gears 4, Crackdown 3, Fortnite and Days Gone impressive. I'm sure there are other technically notable games using UE4.

On a side note, it possible moving a game from UE3 to UE4 isn't too difficult. However, the Batman remasters showed a simple port would have been better. While Gears of War: Ultimate is basically a great port and engine "upgrade" with improved visuals. Probably could have been 60 fps if they stuck with UE3 though.

A hammer is a bad tool when you try to screw in a light bulb. All you said comes back down to developers using the wrong tool for their job. If a developer is forced to use a certain engine then that's mostly out of budget constraints. Of course you'll get a bad result if you use a cheap tool to make quality art. But cheap tools are perfectly fine for simpler projects.

The load times of UE4 are awful! I gave that a mention in my previous post.

That has really become apparent in fighting games (SFV, Tekken 7, SCVI), I literally get bored just waiting for a fight to begin and lose interest. Meanwhile MK X/11 and Injustice 2 load quickly thanks to their engine.

Load times are actually a lot faster on the X1X, probably thanks to the superior CPU speed. Frankly, if you're gonna play UE4 games consider a premium console.

Mass Effect 1 looked brilliant on Unreal Engine 3 at the time... Same with Mass Effect 2, Especially on 360. - The engine wasn't regarded as archaic by that point.
But by the time we got to Mass Effect 3 the engine limitations were starting to become readily apparent with blurry textures, skyboxes with limited resolution,  that sort of thing... Still a highly artistic game, but the engine was certainly holding it back compared to say... What Frostbite could deliver, especially on PC.

Unreal Engine 2.5. But it was modified and added a ton of new effects to water, lighting and shadowing. - Helped rewrite some shaders for Bioshock back in the day to enable backwards compatibility on older GPU's just like with Oblivion.

In theory Bioshock 1 and 2 could have been ported to the Original Xbox as the engine was capable of running on that hardware really well.

Mass Effect 3's underwhelming presentation might be more reflective of Bioware than the engine. Frostbite delivers great visuals but primarily just when DICE is using it for Battlefield games. Also, the Battlefield games tend to treat PC as the lead especially during the 7th gen.

I think the OG Xbox could have handled Bioshock in some form. Just look at the iOS version of Bioshock, that looks much worse than games like Doom 3, Half Life 2 and Riddick on the OG Xbox. What I was really saying is the project likely changed very much over what might have been planned for 6th gen hardware, it just kept the same engine. That's why UE is so popular though, it certainly does scale.

I don't doubt they could have; speaking in purely mechanical terms Bioshock 1/2 weren't highly complex games in terms of having huge levels with lots of moving parts or tons of characters on screen, all you'd need to do was massively cut back on graphical fidelity and maybe break up the levels with loading screens like in Doom 3. The original Xbox ran a port of Half-Life 2 after all.

Still, I'm glad they came to the 7th gen instead as the increased graphical power allowed for a more atmospheric experience. The beautiful, creepy, haunting visuals were a big part of what made Bioshock so incredible, as such I can't help but feel they couldn't have lived up to their proper potential on 6th gen hardware.

While I agree that UE3 has shown some excellent results on current gen hardware, (Outlast II especially) I'd also say UE4 has produced some beautiful games like Hellblade and Yoshi's Crafted World. 

Pokemon's Gen 4 engine is the worst I've ever come across.

DPPT and HGSS were all great games, but the engines they ran on were so so awful. A minute to save, half the speed of RSE/FRLG, lag in places that utilised 3D models. It seriously detracts from them to the point that even playing them as a child I'd just go back to the GBA games because they were so much smoother to play; I can't fathom playing them now without an emulator put on double speed. The leap between Gen IV and V was incredible, the engine for BW was fantastic, I wish they'd remade GS in that instead.

Don't like whatever was used to make Minecraft.

As I mentioned already, the iOS port of Bioshock is probably the best idea of what a 6th gen port could have looked like. Bioshock is a visually stunning game that has an almost ageless presentation. It made great use of lighting and shadow effects that simply weren't available on 6th specs. It wouldn't have had the same impact even on OG Xbox.

I did mention some impressive UE4 games. Hellblade on Switch is not a great looking game in my opinion, but that game wasn't built for Switch anyway. The Yoshi game on Switch has an unusually low resolution albeit 60 fps. Maybe the Yoshi game should have been UE3, could have had similar visuals with a better resolution. I mean its like 600p? That's pretty bad,

Hellblade on Switch does suffer that characteristic unevenness of being cut down from stronger hardware but at its best it looked better than anything else on the platform so far in my opinion.

As for Yoshi, it may not be the highest res game but to me it still looks beautiful thanks to its charming art direction and fantastic materials.