That depends on what the base game really is. Right now, it’s not an MMO, it’s not a survival game, it’s just Minecraft with better graphics and a team that’s desperately trying to please MMO players, survival game players and Minecraft players.
I happen to be one of those Minecraft players and I’ve enjoyed Conan Exiles since its Early Access. I’ve sunk around 4k hours into it and I only stopped recently, because they’ve made Siptah into a giant slot machine. Even thought Conan Exiles has always had RNG elements in it, there used to be much better balance between RNG and the rest of the content. That balance started shifting around the time they revamped the Unnamed City, and it culminated with Siptah.
The overreliance on RNG might be fine for you, if you’re used to playing mostly MMOs. But not all of us are MMO players, or enjoy the excessive grind, or care that it’s been working for over a decade in such games.
I’ve had that luck often enough when I had my clanmates with me. That’s what RNG is like: your experience can be drastically different from mine because you get different dice rolls from mine. 
Make the content more challenging. Take the Red Mother, for example. As she is now, all you need is a decent enough armor and some daggers. There’s no real challenge in defeating her. The legendaries she drops have such a low percentage, that people come to the forums to report a bug with her loot table. Does that seem like a working solution to you?
Again, the details of how you make the content more challenging would depend on which crowd you’re trying to please. For players like me, it would be a boss that you have to prepare for, with special gear that you have to farm up over time. I’m not an MMO player, but from what I’ve heard from MMO players, it sounds like they might enjoy a boss you have to team up with other players to defeat. Those are just two solutions that would be better than simply saying “lol make the loot super rare”, but you’ll notice that those two solutions go in drastically different directions.
And that’s the crux of the problem with Conan Exiles right now: the devs don’t want to commit to any specific direction and they keep trying to please everyone, so we end up with the lowest common denominator, i.e. “stick it behind the RNG”.
Funny you should mention that. I’ve suggested something like that several times before, because even that system is better from what we have right now.
Most of the RNG in Conan Exiles follows what I clumsily call “deterministic cost for random reward” system. In other words, you fight a boss, or clear a dungeon, or whatever, and that’s pretty deterministic, but the drop is random and you have to keep doing it over and over again, ad nauseam.
What you described there is what I call “random cost for deterministic reward”. You fight a boss, or clear a dungeon, or whatever, and what you get from it is a random drop of an ingredient you need to craft the reward you want.
Those two look interchangeable, but there’s a big difference in perception. It gives players like me a sense of working towards a goal, through my own effort, instead of gambling on whether I’ll get the item I want. And yeah, there’s still gambling involved, but the whole point is that it doesn’t feel like gambling anymore.
First, what does it mean to “complete” the Conan Exiles endgame? Second, should you need legendary items for that?
There’s nothing “hurr durr” about that. Conan really ain’t no MMO, so you can’t blindly follow MMO best practices and expect players to be happy with that. If they had advertised it as MMO, I wouldn’t have touched the game in the first place.
You wanna know why? Here, I’ll quote your own post:
What are the top complaints about Conan Exiles?
- The game doesn’t start for a whole bunch of players.
- Every patch breaks something big, be it a boss, a dungeon, missing textures, or whatever.
- Cheaters keep cheating, despite all the promises of a solution.
Sure, the endgame in ARK might be more fun. I don’t really know about that, but it’s a moot point as long as the game is in this state. On top of the problems with bugs and cheating, nearly every big update introduces sweeping changes that aim to solve one thing and end up messing up something else. The new benches are one example, but I think my favorite so far was the fish trap change: instead of cutting down on fish trap spam, it just traded it for compost heap spam.
No, I’m not “creating a mystery” by challenging your preconceptions of what the game should be. I’m merely pointing out that you have a certain mindset, but not all of us share it. From your post, I’m tempted to assume that you’re someone who plays a lot of MMOs and that your expectations for Conan Exiles stem from that, but I’ve known many Conan Exiles players who don’t care for the same things you do.
I don’t like what the new benches did to the desirability of thralls, either. But you’re the one who chose to reply to Taemien’s assertion that “RNG does not equal a challenge” with a tirade about how RNG is The Way. It’s not. It’s just a tool in a game designer’s toolbox, but Funcom treats it as the golden hammer.