Well. I would use this in combination with a technique. Say I use Earth Spikes, I genjutsu them while jumping to make them think, Oh, no spikes there xd
The limitation is probably eye contact, especially if the opponent expects genjutsu from you (Dojutsu Users) they will say "Focus on your chin instead of eyes". Which is where I am puzzled as to how to get around that.
It doesn't require eye contact, only a small sequence of hand seals. (when eye contact is needed, it states so in the jutsu).You can alter small pieces of landscape to your will, which can disrupt an opponent specific move. Creating a tree where there wouldnt be, so you can hide behind it, and launch techniques from there. Covering up a large hole, where the opponent would then try to run over, and fall in.
Limitations- size of area altered, it seems like this can only do rather small objects, not like altering the entire battlefield, but a specific object, range, eye contact
Im guessing here, but I would say most genjutsu requires eye contact from the opponent.
Notice the range. Short Range. You can only perform this technique and most genjutsu in short range of your enemy. To alter his chakra flow you need to be close to it. Actually, if i'm not mistaken, there is only one genjutsu that works short to mid range and its an A-Rank. Cannon one that is. this is the main disadvantage of Genjutsu: Range.
Now, did you understand why genjutsu is short ranged and why in battle that can be bad?