Doesn't it seem like there are alot of things missing in itemization?

For one, barring a few specific champs, usually you just build the same thing depending on your role. Marksmen almost all end up with the same 4-5 items, tanks get to change it up sort of, but basically the enemy team comp chooses their build for them since there aren't enough options to have much variety apart from the core. If you want health the most you'll probably have the same build as any tank that wants health most, same goes for armor and MR. For mages it seems like either you're tanky or not, and unless you have a manaless champ you'll probably end up with the same items as any other mage that chooses the same route.

While pushing more diversity in the champs themselves, the items seem to be getting narrowed more and more. Some examples: Why are there no MR/Mana items anymore? Why is building mana the only way to get CDR on an armor item? If a tank needs attack speed and tankiness, why is wit's end the only option? Why is crit only on glass cannon items now? Some of these things seem very strange. Tanks/bruisers who need attack speed still need attack speed when they are not facing much magic damage, but Wit's End has been the only option for years. Some champs don't use mana, so when they need CDR and armor they are forced to buy two seperate items for it and that doesn't work out too well most of the time(if you need cdr, health, AND armor... well damn :) ). I think part of it is where they don't mind axing an item completely if it doesn't get much use. That doesn't seem like the right way to go at all. For example, what did Atma's actually hurt about the game? If it's only good on one or two champs but isn't broken, there isn't really a need to remove the option. It just shoehorns everyone into the same build over time when you remove the more obscure or less used options.

It gets very boring to feel like there's a static build for just about every role that you might swap out one item on occasionally. I know they have been pretty reluctant to add new items to the game but i think this is something that's getting more and more important the way the game is going. There should never only be one viable way to build a character. If that's the case, the items become more of a mandatory chore than a build choice.