Wow that's interesting... They really look nothing alike. Look at the fidelity of the character models, the color palette, the general noise level, the shaders, the normal maps, the lighting etc.
You probably thought DOTA 2 looked like LOL I guess...
These are the most similar images I could find and even here the differences are huge. Congratulations they both have grass. League's art style was always just a poor rendition of Blizzard's. If you expected Blizzard to make something wildly different than the style they developed you are bound to be disappointed.
Troll away though if you like.