Ideas for itemization (generally speaking)

Right now I feel like a huge problem with item diversity is that there isn't a big difference between generalist items and niche items.

Now when I say generalist items I mean items where the whole idea of them is to be stat sticks and not much else, these items are typically what are bought first for a specific class (Example would be Morellonomicon, Youmuu's Ghostblade, Infinity Edge, Sunfire Cape, Black Cleaver, any jungle item, etc.) They may also come with passives that are essential to the class buying them.

Talking about niche items, these include the items that are bought within sub-classes and are rarely shared between sub-classes, these items also include ones purchased for specific situations (Rapid Firecannon for Siege marksman, Randuin's Omen vs. crit heavy teams, etc.) These items most commonly come with actives or unique passives that apply to specific situations, creating high synergy moments that will feel like a power spike.

The problem with generalist and niche items, however, is two fold. To start off, the difference in stats between generalist and niche items are barely noticeable in most cases and therefore require the passives and/or actives to be on the weaker side. This point also applies to the idea that niche items also offer enough stats where the niche effects can often times be seen as overkill (note: Rylai's Crystal Scepter from just after the Mage Class Update). Some items, however, pull off the niche item definition beautifully where the item does offer some bit of stats for the sake of game scaling, but a majority of the power lies in the actives and/or passives. The two best cases of these items are Locket of the Iron Solari and Redemption. I'm not saying the items are perfect, but they exemplify what a niche item should look like: a low stat item with effects that will scale with you as the game goes on.

In an ideal world, niche items should be low gold-efficiency in terms of the stats offered but make up for it in the power of the active, truly catering to the niche at hand. With this ideal world, the way the game would play out is by having the first two fully purchased items of the game be one generalist so the necessary stats are given to start scaling up + boots (but even boots could use some more diversity and niche-setting). But as the game goes each, each next fully purchased niche item would involve higher combine costs to really make players pay for those passives and actives while making the niche item feel like what one would expect to be an In-Game Keystone. Here's an example:

Let's look at as compared to the other Crit + attack speed items. As of right now, the item already has the stats to be considered a niche item (lowest attack speed of its competitors by quite a bit) but currently lacks a true siege-power passive. In order to make this item more drawn out for its niche, an idea could include removing the bonus speed of gathering Energized stacks but making the Proc deal triple damage to structures and giving it a tiny base damage scaling increase (50-120 >>>> 50-150). With the adjustments to be more powerful for structures the item could then stand for a combine cost increase from 600 to 900 or 1000.

I'm going to stop here because I think the point has been made and I don't want to give a list of all possible changes to make items far more niche and less of stat sticks. The goal of this idea would be to make the effects of items feel like powerful additions to the player that really emphasizes and style of play or goal of the game, rather than just being something extra on top of an already high amount of stats.