It is very easy to create someone who is tailored to create an interesting fight, especially when you are dealing with a nigh unlimited world. Most interesting fights are not really interesting because of duration or context but because of the intangibles. For example, the best fights in most any anime I have ever seen is Samurai Champloo. The fights there are basically from 15-45 seconds long and involve two people, most always with swords trying to kill one another. In the end, someone dies. It is the beauty of their motion and the symetry of the choreography that makes the fight interesting, not the venue or means.
Likewise, in a manga, the fight is made interesting by how things are executed not what they are. It is possible to write a very interesting fight that contains literally one blow thrown. For example, in hunter x hunter, the kidnap of Lucifer is technically a fight, but it lasts literally a second, each party getting one move in. Robins fights need to be written more carefully than others but they can still be made very interesting.
For example. Lets say, She fought Kumadori. When he or any memeber of CP9 uses Tekkai, her clutch is nullifed. In this particular case Kumadori also has a non directional appendage with no joints, his hair, meaning, no matter what she does to his limbs he can still strike back. However she is likewise not limited to just spawning hands and appendages. She as an assassin has been shown to use weapons twice, and thus we have another possiblity.
Imagine if you will, robin, with 6 guns being dragged up a wall by a delphinum in an effort to evade Kumadori's hair, while fireing rapidly at him. She can't risk a clutch and it would do her more harm than good. Perhaps the ultimate solution is to spawn a hidden arm, wait until he tries some move, then throw a knife at him. He dodges goes in for the kill and the arm grabs the knife and stabs him in the back.. a la crocodile.
All it takes is imagination and willingness to work within a set of boundaries. Many can be resistant but not immune to Robins power, through strength, devils fruit or gimmik as long as the writer is willing to play around and be creative… and that....that I don't see as a problem.