I've collected some data from DOTABUFF on hero pick and ban rates for TI4 versus TI3.
I've laid them out in two infographics as follows
Hero Pick Rates in TI4 versus TI3 sorted by frequency
This shows you what the average game team composition looks like in TI4 versus TI3 - the popular carries, supports, etc.
Hero Pick + Ban rates sorted by TI4 vs TI3 variance
This shows you the relative changes between TI3 and TI4. In particular, you can see Lycan and Brewmaster were ignored in TI3 and have become staples in TI4.
Most hero changes are self explanatory - they're more picked in TI4 because they received buffs - but there's a couple of subtleties.
Lycan - while receiving no direct buffs, his role has changed substantially to how it was in TI2 when he was last dominant. The nerf to wolves hp made it almost impossible for him to jungle at a decent speed, however they got buffed with earlier invisibility and crazy hp regen which allows him to harass supports out of the lane. Also, pushing lycan got a big buff when Midas and Helm of the Dominator were changed to not eat Necrobook units.
Windrunner / Darkseer - while receiving no direct nerfs, these were previously the "premier" offlane heroes in TI3. Since the offlane was changed to be less unforgiving, it made it easier for other heroes to lane there.
Chen - while receiving no direct nerfs, the rise of Doom and the higher frequency of Midas pickups made him unviable to play as his creeps would keep dying. Also with the rise of Ancient Apparition his team heal was rendered useless.
I've laid them out in two infographics as follows
Hero Pick Rates in TI4 versus TI3 sorted by frequency
This shows you what the average game team composition looks like in TI4 versus TI3 - the popular carries, supports, etc.
Hero Pick + Ban rates sorted by TI4 vs TI3 variance
This shows you the relative changes between TI3 and TI4. In particular, you can see Lycan and Brewmaster were ignored in TI3 and have become staples in TI4.
Most hero changes are self explanatory - they're more picked in TI4 because they received buffs - but there's a couple of subtleties.
Lycan - while receiving no direct buffs, his role has changed substantially to how it was in TI2 when he was last dominant. The nerf to wolves hp made it almost impossible for him to jungle at a decent speed, however they got buffed with earlier invisibility and crazy hp regen which allows him to harass supports out of the lane. Also, pushing lycan got a big buff when Midas and Helm of the Dominator were changed to not eat Necrobook units.
Windrunner / Darkseer - while receiving no direct nerfs, these were previously the "premier" offlane heroes in TI3. Since the offlane was changed to be less unforgiving, it made it easier for other heroes to lane there.
Chen - while receiving no direct nerfs, the rise of Doom and the higher frequency of Midas pickups made him unviable to play as his creeps would keep dying. Also with the rise of Ancient Apparition his team heal was rendered useless.
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