I think i'm pritty clear about the glassdoor reviews not being 100% reliable but there are 2 other points in the thread you seem to have skipped.
The leaked roadmap is even less useful - it doesn't say why JWE "can't be fixed". If it was something to do with the engine, it wouldn't be any better in a sequel either, so it's probably bad implementation decisions elsewhere if they think starting over will help. That's evidence
against your hypothesis, not for it.
The quality of the game in general ... well, "everyone agrees" that Unreal Engine is really good and there have been some absolutely
terrible games released with that. You can program bugs into just about
anything. The main issues with the game are not "engine" ones -
You've proven that Frontier have issues developing Elite Dangerous, definitely ... but a quick look at the game would show that, it hardly needs proving again. There's absolutely nothing to tie this specifically to the "engine" rather than to the bits built on top of the engine. Planet Zoo ... same engine, they don't seem to be having serious scheduling or quality issues with it.
Looking at the top 30 open voted bugs ... there's some graphics issues and some networking issues which
might be the engine (or might not), but over three quarters of them are design or implementation issues which have nothing to do with the underlying game engine at all.
Even if there are serious issues with the Cobra engine, that doesn't mean a different engine would be better:
- Elite Dangerous: custom in-house engine (released)
- Star Citizen: uses a commercial engine, heavily customised (several years behind schedule)
- No Mans Sky: custom in-house engine (released)
- X4 (and previous iterations): custom in-house engine (all released)
- Dual Universe: a commercial engine, but a really obscure one that's specifically designed for space-scale environments (years behind schedule but might be released soon-ish)
There's a definite pattern there. I can't think of a successfully released open-world vaguely-like-Elite space game (constrained combat-only games, yes) which has used a commercial engine ... and Dual Universe would
barely be an exception if it does get finished since they're not using a game-focused engine for it.
The problem is that the issues with producing a game set in space - where objects a metre away and objects a few AU away can both be relevant at once - or where entire planets need to be generated and simulated at once - is that this is a set of problems
way outside the scope of conventional mainstream game engines. They're not optimised at all for that use case - because there's about ten games
total which would need it, and optimising for that makes all the Yet Another FPS/RPG/RTS games much less efficient, which is not, commercially, a good thing for engine writers to do.