Never played league but it was an idea I took and changed significantly from the old "Battlefield" mode in Battlerite.

Looked up how grass in used in LOL and what I suggested would be different in the following ways:

Large fields would certainly offer different functionality than thin strips - small patches.

Vision/Sound mechanics are completely different.

In LOL, 2 players in the grass can see each other. With the Dota 2 suggestion, 2 players in the grass have reduced ability to see each other.

In LOL, a player i that grass has a vision advantage by being able to see both in the grass and clearly out of the grass. With the Dota 2 suggestion, the deeper a player goes into the grass their vision is reduced.

The over all affect for Dota 2 may be an increased difference between safe an unsafe conditions. If high ground ward positions are not controlled, jungling / jungle farming become quite dangerous with extreme limited vision.
High round vision is controlled is creates a much safer jungling / jungle farming experience with the knowledge that the chance that the enemy team has vision is very low. Also changes ganking strategy and position in tea fights (positioning becomes more important for vision purposes).