Hmm, I don’t see why not. I personally made a hack n’ slash in Unity in about 4 months… Biggest part is artwork, it takes forever if it’s to look good. Using modular systems and re-use with vertex painting is probably a good idea, or swapping out materials.
If you’re a one man band, you can with a lot of work make the next Skyrim with UE4. Just depends how much money you have, even as a team of 15 (broken into six artists, five coders, one manager, one HR with me and a PR guy) we still buy a lot of tools / asset packs which we modify.
Extensively use things like quixel, use autorig solutions, faceFX for facial animation, we have Modo for speed modelling, maya LT 2015 for more complex meshes and animation, agisoft photoscan for some mesh capture. SpeedTree for foliage, for water / rivers etc. we’ll just buy and tweak most likely. Mocap we have flex3 cameras and a couple of PS4 camera’s too… Probably more stuff lying about to be honest…
I had most of this stuff even before I started an indie, when I was working on my own stuff. Apart from that if you are dreaming big just scale back and make design decisions based upon what you can get away with. Like we dropped the TOD system due to performance issues, were constantly splitting the terrain up and trying to keep within the bounds of the engine so we don’t have to make bespoke solutions.
Apart from all that, UE4 pretty much has all tools covered. The only thing left is UI / AI / sound / Main character skills and storyline (all the cut scene goodness).
I will admit, we did get a lot further faster in Unity. But on the whole, the game does look better…