Dota is marked as "controversal" because it kinda succeeded Warcraft 3. But not as WC4 but as the sequel genre to WC3.dota isnt a sequel, ALBW reused none of LTTP assets (these are very confusing choices)
Also assets are more than just graphic models or sprites. If you copy / re-use a complete world then that world is also an asset. Seems like the common definition for assets are: 2D sprites, 3D models, missions, levels, areas, voice, key framing, motion capture, sound effects, music and special effects.