So, here's something that I've been thinking about lately. For as big as a figure as Swain has been in the game, he's probably one of the most restrictive champions in the entire game. By this, I mean he's got so many insane drawbacks that it's really hard for him to really be a threat or even something that anyone would really consider good in most cases. In particular:
1) Swains cooldowns are ridiculous. He's got nothing in his kit that allows him to deal anyone with any remote amount of speed, and it restrains him in terms of kit to being FORCED to pick up at least one, if not more, CDR item to even have close to the same amount of tricks or damage that another mage can't do naturally. At the very least he needs at least one spell other then his Ulti to allow him to farm, considering the insane mana costs of his R.
Suggestion for buffs: Knock down the cost of either Torment Or Decrepify.
2) Swain's mana cost are also very high. Part of this makes sense thanks to his passive, but as it stands, I still find his passive fairly weak in actually being of any use to Swain. He's still chewing through all of his resources to do minimal on the field or in battle and it's damn near required to grab at least ONE Mana item, again if not more. This combined with the ineffective way he can kill minions, he's pretty much not being able to keep his mana up no matter WHAT he does.
Suggestions for buffs: Make his passive more like trundles, where he get's mana back for EVERYTHING that does, not just things that Swain kills. Not only is it a bit more thematic for Swain, but would help out a lot against the people who can harass him out.
3) His spells in general are lackluster. His Q is outdone simply by grabbing Crystal Scepter, his W is restrained by the problems from above, and most of his power is locked away from him by his E, which means he's simply not able to do anything to his enemies because they'll use their escapes the moment he even gets close to use it, usually before because of how massively he telegraphs his effects. There's got to be something that needs to be changed here to give him something of an advantage in a fight.
Suggestion for Buff: E would be fixed alone by the other two changes, Q frankly just needs to slow enemies more at the higher ranks (Frankly, something like 60% slow might work), and E maybe needs to lose some of the amplify so the buffs to everything else can work.
Really, I'm just trying to see a game where Swain can be chosen as a CC heavy Mage in battle, but right now, he's out done pretty much by everyone who not only has a great deal more range then him, but simply can do it without having to climb a mountain and a half to do it.