PLEASE READ- This tier list is for players looking to play heroes that are currently strong in both HL/TL. This is my personal list so it will probably be different in some ways compared to yourself or other pro players tier list. Every Hero has a good chance to win games but some require A LOT of games to become a master of the hero that I placed in lower tiers to really shine in games and help you climb ranks. With all of this in mind please enjoy :)
For tier one these Heroes are just strong at what they do above other heroes in the same category/role. Off laners are in a very odd position due to not having THAT many "OP" Heroes for that role so there's a lack of off laners for tier one... ( Mal'Ganis not an off laner :P )
Tier two Heroes, While not being AS strong as the tier one heroes I think these Heroes are still strong at what they do. If you know how to play Heroes in this tier then you will perform well. Some of these Heroes are map dependent but CAN work on almost every map.
Tier three we start with Heroes that aren't always the best to pick. Some Heroes just get out classed by others BUT if you spend some time practicing these heroes they do work in certain comps your teams draft. You should have a plan and good reason on why you pick some Heroes from this tier in order to give yourself and your team a strong chance to give you an advantage and win.
Tier four are Heroes that have either been nerfed down or just don't have as much impact in games compared to other Heroes. Like I stated earlier these lower tier Heroes CAN still win but require a lot of practice and good reason for picking them for your team. If you're willing to put in a lot of hours and games into these Heroes and feel comfortable trying to climb with them by all means go for it as this is my personal opinion and I don't judge anybody unless you troll with Heroes.
Now finally we're here... the bottom of the tier... tier five for my list. Almost every time I see the Heroes in this list, it almost feels like the games are so much harder to win but not impossible. These Heroes are just lost in the void of either "used to be good" or work in VERY...and I mean VERY rare occasions. Play these Heroes at your own risk :)