Again; this is an experience issue on your end, not a game issue on theirs. If the boss was near impossible, it’s an issue with your build or ability. You can take this how you like; looking for external reasons is easy, introspection and improvement is harder. Do the boss yourself, on easier difficulties, a few times, so that you can see the mechanics and their tells without being immediately killed. Nothing in the fight isn’t heavily telegraphed, and the time jump mechanic literally takes you into a different universe where you cannot be hit by abilities.
Every game will reach that point at some time - D3 even faster than most. The reality is that the LP system increases the longevity of usefulness of exalted items specifically because of the RNG you are discussing; if you don’t wait for a 4 mod useful item as you did, you need multiple of them to get the outcome you want.
Again; you don’t need the exalted version of the item at all to do anything short of 200+ corruption, or even much higher depending on build and ability. And, you went in to an event that you found significantly challenging knowing that you had a 25% chance to fail, instead of looking for an item with 4 good items and thus a 0% chance to fail.
Not sure what numbers you are talking about. Prior to the 1.0 release the biggest 24hour player count was around 40k, it jumped to 260k players on release and is still sitting at ~120k 24hr peak as of yesterday. That is ~45% retention after 3 weeks, and that is absurdly high retention for an arpg - Path of Exile has never had anything close to that, as an example.
He said 3 of the 4 mods were good for him, so he was right that it’s a 25% failure chance. That said; it’s very easy to get an item with 4 potentially useful mods before you use it on a 1LP item if you don’t play enough to get multiple 1LP uniques to roll on.