League of Legends never stepped on Warcraft trademarks as far as I know, even though they were a clone of DOTA. Valve and others battled it out legally with Blizzard over the DOTA name and eventually won, but this was definitely not Blizzard's intention - and of course they didn't use any Blizzard-created art in the final game.

Note that I don't think anything in the W3: reforged terms of service would prevent a new game being created based on a W3 mod, it would just prevent it from using the same name and art as the mod. This is exactly what happened to all other successful mods, with Dota2 being pretty much the sole exception.

Also, Riot mostly proved that you don't actually need the artwork or names to be massively successful - you just need to recognize a good idea and be the first to market with a polished implementation of it.

> Valve and others battled it out legally with Blizzard over the DOTA name and eventually won, but this was definitely not Blizzard's intention - and of course they didn't use any Blizzard-created art in the final game.

Had Blizzard owned DotA IP, I believe Valve would've had to steer much further away from the map, character and item design. IP extends beyond just art and naming, see e.g. Tetris vs Mino [1]. The case wouldn't have been a guaranteed win for Blizzard, but the early releases of Dota 2 were really closely copied from late releases of DotA, so the argument is there.

> Note that I don't think anything in the W3: reforged terms of service would prevent a new game being created based on a W3 mod, it would just prevent it from using the same name and art as the mod. This is exactly what happened to all other successful mods, with Dota2 being pretty much the sole exception.

Keyword being successful. Many maps have standalone ports that kept their predecessor's name [2][3][4][5], but only Dota 2 is really successful. And again, I believe these wouldn't exist or would've made large changes if Blizzard owned the IP of Warcraft 3 mods.

[1] https://arstechnica.com/gaming/2012/06/defining-tetris-how-c...

[2] https://store.steampowered.com/app/578350/Element_TD/

[3] https://store.steampowered.com/app/537680/Sheep_Tag_2/

[4] https://store.steampowered.com/app/469600/Legion_TD_2__Multi...

[5] https://store.steampowered.com/app/676580/NEO_Impossible_Bos...

Given that League of Legends, Dota 2, and Blizzard's own Heroes of the Storm all share virtually the same map today, and are not engaged in any IP battles over it, I don't see any reason to believe Blizzard owning the original IP of the DOTA mod would have made any difference in terms of blocking the map design from being reused in other games. If anyone could have owned this map design, either Riot or Valve would have already sought to block the others from using it.

That's really stretching the meaning of "virtually the same map". LoL and Dota 2 maps look similar on the minimap (HotS not so much), but they're drastically different when you start looking at points of interest and juke paths. In contrast, Dota 2 used to have almost exactly the same map as DotA (differences being shops and hero selection, which were changed from ingame units to actual UI menus).

Not to mention that Dota 2 also copied the exact skillsets of heroes and items. Not just likeness, but even most silly bugs that were due to the Warcraft engine.

Edit: Anyways, this is getting sidetracked. My point is that Warcraft 3 was lax with intellectual property for the longest time, and mods like DotA most certainly leveraged that.

Sure, and I am contesting that point by showing that League of legends succeeded in creating a game based on DOTA that didn't need any of the DOTA-related IP. So, while it is true that the DOTA team / Valve from Blizzard's laxness at the time of W3, their succes didn't hinge on it, as Riot proved.