User blog comment:Hyxaru/Rylia's needs a 'hextech-spellvamp removal' treatment/@comment-1330314-20160711061332

I agree with a fair amount of this. Rylai's perma-slow has been sort of hand-waved as a lesser evil by Riot, but the gameplay it creates on several champions, including many of its core champions, isn't particularly interesting, and those champions also end up being balanced around that slow to a point where they can't really function properly otherwise (Aurelion Sol is a good example, as you mentioned). To be fair, it does differ from spell vamp in that it's useful on a much wider variety of champions, and is general enough to not have to be balanced around a ton of different spell paradigms (even though it tends to be much more effective on low-cooldown spells), and a potential "excuse" for its perma-slow is that it's heavily tied to mana usage in most cases, though that makes balancing awkward on manaless AP champions, who tend to be in awkward states of balance anyway (Rumble's been tough to balance because of his manalessness, for example).

At this point, the item's also competing directly with Hextech GLP-800 in both stats and niche, though the latter is the better-designed item: the Catalyst in its recipe gives it a dynamic kind of tankiness that works better on mages, also less abusable on manaless champions, and allows its build to be less awkward (Giant's Belt isn't usually a great purchase on a damage-dealer, which is also why Frozen Mallet was historically unpopular on many AD champions), and it offers a brief, powerful instance of CC, instead of spreading it thin over a long (in this case, potentially infinite) duration. I think the solution may not be to add special cases to Rylai's, which would make it more complicated and awkwardly balanced around the champions it caters to, but perhaps instead to remove it and have GLP-800 take over completely. Perhaps that item could even get more experimental and have a briefer root instead of a slow, particularly since Hextech Protobelt innovated by being the first item to offer an additional dash, and succeeded despite expectations that it would break certain champions.