Of Diana, AP Fighters, and Nashor's Tooth

First, allow me to preface this by saying that I was a top-lane Diana main through Season 3. I built her bruiser and capitalized on the power of Sunfire Cape paired with magic penetration in order to best abuse the strength of the item while allowing it to scale better in the later game than it otherwise would (Sunfire Abyssal is a great combination of damage, health, and both defensive stats). Runes and mastery points were constantly swapped in and out to find the "best" combination, but it was almost always an up-hill battle for a variety of reasons, one that was hard-fought.

I picked up Diana as a counter to the ever-popular Riven, who with knowledgeable and careful play could survive her potential all-in (W can make trading with her very scary), interrupt her combo (E'ing the third Q), and avoid her ult (R'ing at close range puts you on the other side of the opponent). It was hard work, but I eventually persevered and managed to achieve a win-rate with her that I was very content with. Then several changes went through (notably the heavy nerf to Sunfire Cape and the mastery changes which heavily favors the offensive tree in lane) and it doesn't work anymore. There's so little support for AP Bruisers -- specifically AP-oriented bruisers that are reliant on auto-attacks -- that without relying on Sunfire Cape, it just didn't work out, and there's plentiful reasons why this kind of archetype simply doesn't work at present.

AP Bruisers rely heavily on very strong AP itemization that allows for both offense and defense (Zhonya for Armor, Abyssal for MR, Rod of Ages / Rylai's for Health, and so on), but because of this they can't heavily invest in an item that only gives one or the other. Raw offensive items are a no-go, and often these kinds of champions need so many different stats that they can only allow for one, maybe two purely defensive items without compromising their effectiveness. However, there is one area of itemization that AP Bruisers have effectively zero access to -- sustain.

There are zero strong AP Fighter items that allow for sustain. Mana sustain is very rarely a problem for assassins because they just kill you in one or two rotations on top of very good options for keeping it topped off, but it is a very big problem for Bruisers who rely on multiple rotations to whittle you down. Athene's used to be a decent selection, but its MR was nerfed to the point where it's largely ineffective, and its mana regen isn't even as good as Morellonomicon -- a raw offensive option -- half the time. Health-wise, the only options allowed are Will of the Ancients and -- to an extent -- Hextech Gunblade, but Gunblade is a raw offensive option that doesn't give enough survivability to warrant its price and slot and Will of the Ancients -- while rather good -- doesn't offer enough for Fighters. It's rather good on champions like Vladimir or spell-focused Rumble, but they're not auto-attack reliant and don't have to manage a mana pool: they have a free slot to burn.

AD Champions have the omnipresent lifesteal, often in great quantities. AD Champions even have access to Essence Reaver if they were so inclined, meaning both their health and mana pools are sated, and it is somewhat telling that despite giving health, mana sustain, and CDR that Essence Reaver isn't popular; despite offering so much in a single item slot, the other choices are oftentimes better. 20% lifesteal with a shield. Attack speed, lifesteal, and damage based on enemy life. AoE lifesteal that gives an active AoE nuke. Essence Reaver isn't even a bad item -- it's actually rather good, and I even use it upon occasion -- but the other options are so grandiosely strong that they're picked up far more often.

Nashor's Tooth looks like it's trying to be an AP Fighter item, that option that fighters can make use of to increase the potency of their auto-attacks, yet despite seeming tailor-made for them... it just ends up taxing your item slots and gold while giving you a very situational source of extra damage. It offers you neither survivability nor sustain to back up its offensive power... and, in all honesty, you'd probably be better served just getting a Wit's End end; though it doesn't scale with AP like Nashor's does, it still does everything else and likely even does it better if you're going flat-pen with Sorc Boots and Abyssal.

Essence Reaver is a decent niche pick that is crowded out by the other picks because of how strong they are. Nashor's Tooth is a niche pick that is crowded out because it's simply not effective and because of how strong the other picks are, both niche and mainstream. If you're an auto-attacking mage, just pick up Lich Bane and you've got movespeed on top of an empowered auto. If you're an auto-attacking magic-dealer, pick up Wit's End; it's not perfect, but it offers more bite and bark than Nashor's Tooth does. It's why I think that Nashor's Tooth should be slightly repurposed to fix the sustain issue.

Instead of dealing extra magic damage on hit, have Nashor's return an amount of health/mana based on AP. During the time of Feral Flare, I jungled the heck out of Diana because it was the first time in a very long while that I was able to play her bruiser. The mix of sustain, attack speed, and magic damage on-hit afforded through that item synergized so perfectly with a magic-damage oriented kit that it was the perfect item for the slot, similar in efficacy as the other bruisers' sustain options. I'm not necessarily asking that Feral Flare be brought back as it was, but perhaps its design -- at least insofar as flat sustain on-hit, perhaps using a formula similar to current Nashor's -- might be revisited as an option for getting AP Fighters and potentially alternative builds into the game?

tl;dr: Please change Nashor's into an AP sustain item instead of a raw offensive one.