Certain Champions just don't fit into any of the established categories. Examples include 
, all who don't quite live up to the classifications they're given or otherwise have gameplay that warps matches around them. Should there be a classification for Champions who fit this bill? Or is that a case of "that's pandering to something unnecessary"?
Umbral Regent1 votesI personally find it a little unnecessary, but there is a number of good arguments to be raised on either side. I'mma go ahead and throw some arguments up into the air and also discuss classifications of the champion examples you provided, so, pardon the inbound wall of text.
One of the first things I'm willing to say about the Classification of characters between League of Legends and Heroes of the Storm is that, both are somewhat respectively natural to their games. League of Legends, being a fairly big, complex and deep MOBA, has a diverse Class/Subclass system, whereas Heroes of the Storm, what I'd call a "simpler" MOBA that lacks a majority of the meat you'd find in League of Legends (with its own complexities, mind), has a much simpler Class System than League.
As an example, League of Legends has a variety of terms for various champions, from the slow-moving, hard-hitting Juggernauts, to Warden and Vanguard Tanks, Battle, Control, and Artillery Mages, Assassins and Skirmishers, Fighters and Divers, Marksmen, and the various shades of Support - there's a large number of Champions to play, and it's safe to say a good handful won't overtly fit the bill on some of the Classes in the system. But, every game has at least some room for a wild card, and champions like Singed, Ivern, and Teemo are good cases of this.
But, Heroes of the Storm's Classing system is a fair bit more simple, and also in its own way fairly loose. Warriors serve as high-health, moderate-to-low-damage frontline tanks (although they have their own unique niche, such as Diablo who has ridiculous crowd control, or Artanis who's an amazing duelist). Assassins are basically anyone with a high sustained or burst damage characteristic, and can range anywhere from invisible melee bursters like Zeratul, to long range persistent damage threats like Valla. Supports are, primarily, exactly that; Heroes designed to work alongside other Heroes to the team's benefit. Interestingly, while Supports do worlds better when they're working with someone, all but two of them (Lt. Morales and Lucio) have talent choices that allow them to be played solo.
And then, there's Specialists; these Heroes have as wide a diversity as Marksmen do in League of Legends, being unable to truly be defined by a set of common characteristics. There are examples of Siege heroes, like Sgt. Hammer and Sylvanas Windrunner, the co-operative "support-y" mages like Medivh Aran or Abathur, or the really, /really/ odd cases like the Lost Vikings, Eric, Olaf, and Baelog. (and, as one could assume, their mere existence has led to a number of boards posts asking Riot for real multi-character champions). Specialists have a unique identity in that they don't have easily definable traits, but generally work outside of the normal role of "take damage", "do damage", or "reverse damage" - although, siege can be stated as being a common trait amongst Specialists.
But now, that brings me to the issue of ascribing the (ostensibly) simpler Class system of Heroes to the Champions of League. For the most part, I don't personally enjoy the thought of letting unique things from either game intermingle, and, while I know it's inevitable that it will happen, it doesn't settle well with me either way, since I enjoy the comparison of the games and don't like the thought of taking ideas from either and plugging them into the other. But, thankfully, that doesn't have to be an issue, since there are practical ways of doing it. As my example; look at Siege-specialized ADC's and Control Mages - Caitlyn, Azir, Varus, Heimerdinger, and so on. Those would probably fit the bill for Specialists, alongside some Champions with extremely unique mechanics, like the Kindred.
But, even with that practical application of the Specialist role from Heroes of the Storm, that still leaves the four example Champions unclassed, so, I aught to actually get on that now. Singed, in my opinion, fits the bill of Vanguard Tank - if only loosely. He has extreme durability, some moderate CC, and a strong threat presence that's difficult to undermine. Heimerdinger is a Control Mage, since his abilities orient around shutting down areas with his Turrets and using that area denial to force people into places they don't want to be - which is lined up just right for Heimerdinger to throw the rest of his spells at. Ivern is sort of an oddball out of them - he's a Battle Mage (Mages characterized by some small degree of spell-chaining and at least some defensive ability, usually shields), and a Controller Support (Support characterized by being relatively squishy and specializing in ranged crowd-control), and a Jungler at the same time. And, hell, might as well say he's a Specialist, too, considering his unique interaction with Jungle camps.
As for Teemo, he's actually somewhat simple - Marksman + Burn-oriented Control Mage. Since Mages can be split between Burn and Burst, Teemo falls into the former thanks to his Poisons. And since his Mushrooms count as area denial, he fits into the Control Mage category as well.
So, to summarize; lots of words about Heroes of the Storm and League of Legends' Class Systems along with personal opinions on the subject, as well as how Specialist from Heroes can be translated to League of Legends, and Classifying the four example Champions with only one case being titled Specialist (in my opinion, so take with a grain of salt.)
TL;DR for Champion Classes: Singed = Vanguard Tank Heimerdinger = Control Mage Ivern = Battle Mage/Control Support/Specialist Teemo = Marksman/Control Mage
I hope this contributes to your post, and hope further that this sparks at least some interesting discussion.
Häßlich1 votesI don't feel Teemo belongs on there, but the rest of those picks are good for illustrating what you are trying to talk about.
are almost in this category as well, but are slightly too "mainstream" in certain aspects of their play to really place them there.
are all pretty unique in the League. Given the very small pool of champions this could be ascribed to, it's hard to justify a "class" for them other than "Misc."
OurLestrade1 votesSylvanas would be fun to play, but also a bit cancerous :P Although to be honest, if they made a Chen like champion with the brew and shield mechanic I'd main him in every lane. He's probably my favourite individual character in any MOBA I've played :O
