I think I see a couple things being repeated here while ignoring certain factors.
1 is the idea that removing RNG from crafting (and even then you wouldn’t remove it entirely, just most of it) would remove replayability because everyone would instantly get what they want and would lose the reason to play further.
2 is that the RNG is not really that bad and that most people can get the gear they want relatively easily.
Let’s start with 2 then. Getting the right base with a good amount of already usable affixes and then still managing to get the other missing affixes to become what you need to net you JUST and I really have to emphasis the JUST part here, JUST to get a mere T20 is something that a casual player will play an entire league and NEVER archieve it, and I don’t mean the full gear, I mean even just one piece. So the idea that the crafting is in a good spot or needs to be even harder is a ridiculous notion, if anything crafting needs to be far, far more forgiving.
Now let’s tackle an almost fully deterministic crafting for a second like I’ve already said many times before. What happens if crafting potential is removed?
You could say rare items are not worth anything anymore. Let’s be real though, what game actually has rare items as any goal? You want purples or better in any game and indeed you have exalted items here.
Now what are you looking for? Well let’s say your build uses ward so you want ward boots. That immediatly excludes any other boots from the list pool (and generally speaking, with the exception of the belt you always want one base and one base only). On top of this you want these boots to also have an exalted modifier… Well, that’s already a hard find (and that is RNG) But even though this is already a harder find it’s actually harder, because you don’t want any exalted affix, at best you want 1 out of 2 affixes (because let’s be real, you don’t want the sufixes to be the exalted ones unless it’s maybe on the weapon and that’s still a very big maybe since usually you only wants the exalted suffixes on a weapon for a minion build that somehow doesn’t uses a unique weapon). Now we’re already on extremely hard to find boots but there’s more yet. You see, in reality you don’t really want 1 out of 2 possibilities, you want exactly the correct affix so now you narrowed down the chances to beyond extremely low chance, but let me continue. You also don’t want a T6 affix exalted, you want a T7. The level of RNG you are facing from this alone is already monstruous and this is the level of RNG you are facing for every single piece of item. You may get 1, maybe 2 pieces of gear but realistically, you won’t even finish a build.
Now because you like RNG so much, let’s pile more RNG here so you can feel even more fun from the RNG slot machine. You have now found your ward boots, they have a T7 intelligence modifier and may or may not have a second affix you want out of the 4 total affixes. It is unlikely you are filtering from more than base and the specific T7 affix you want at this point because then you go from unrealistic chances of finding to virtual impossibility. Well, now you need to get 3 extra affixes. You start with early attempts at runes of chaos in one affix to hope the RNG slot machine gives you the affix you want before you get to tier 5 and if you hit tier 5 without reaching it, well, now you need to roll on the RNG slot machine with a 25% chance to break the item and a 25% chance to remove what you want removed. If it removes one of the other 2 affixes you haven’t touched yet it’s not technically bad cause you don’t need them, but the more times you atempt to remove what you don’t want, the more likely you are to remove that exalted affix too. Only once all other 3 affixes have been successfully chaosed or removed and then manually added you have a single finished piece.
Explain to me how this is not an already ridiculous level of RNG. Also bear in mind that saying having a T20 is fine or having a T16 is fine. It isn’t. T20 is fine for an early state of completion. That is a you just barely started and this is what you need to start going into empowered monos to look for the actually cool gear.
Now let’s not forget that past this you also have attempts at making T26 items by trying to get an item with a T7, T4 and 3x T5.
Let’s not forget that past that you can still go up to either T28 or T30 depending on whether the item beneficts more for 4x T7 or 2xT7+T5+T4.
Let’s not forget looking for uniques with legendary potential and this is a huge level of RNG as well because normally you want at least 2 affixes you can move in, sometimes you need 3 or even 4 depending on the item base stats and the slot as well as whether the new legendary is a replacement for an exalted item or a replacement for a unique item.
To sum it up. You have already huge levels of RNG in trying to find the gear you want which still makes loot drops valuable, you’d just be moving up the items that are worth looking at from rare to exalted.
You still have RNG for the mid and higher end of crafting while leaving the lower end crafting 100% deterministic.
Because of both of these you’d still have huge levels of replayability. Replayabillity doesn’t comes from your build forming a different time each time you play but rather by the item drops themselves. The crafting is meant to have some level of RNG but it shouldn’t be too high, it should rarely ever be the stop gap. The stop gap is the amount of good finds which combined with the crafting increase the RNG by a bit (in an ideal world it would be by a bit, right now even if there was no crafting potential the RNG would still be insane but it would definitely help at the lower end.
Now, I’ll say the following. While my experience with the current game is not exactly what I’d describe fun especially with the current crafting system, I had a bug that was limiting the crafting potential I had on items. Assuming I can now find better items I can probably get better gear. How much better I’m not sure, but I am sure a T20 is still a pipe dream for a casual player like me.
To me this feels like the item progression still has no direction. There is no clear indication of what level of gear you should have any point nor there is a clear point where you are specifically hunting for the exalted items on the right bases and this is in my view a big issue that the game will have to face when being compared to its competition.