If we only had the Parom tug

The russians are uncertain about letting the Dragon too close to the ISS.  Dragon has had only one test flight after all.  If we only had a reliable and proven Parom tug it could go get the Dragon (or other cargo capsules) from a safe distance.  Only a time proven technology would then approach the ISS. (It would also be useful for delta IV, delta IV heavy, or atlas V launched payloads.)