I personally don't think that two to three feet apart is too close for the two clematis that you have. I think there are possibly several other reasons that one is doing better than the other. First off, Polish Spirit in my experience is a very vigorous clematis that grows leaps and bounds faster than other of the viticellas irrespect of the size of the PS versus the BA. I have both Blue Angel (actually two of them) and one Polish Spirit and neither of the BA grows as vigorously as the PS does.

Secondly, you say that the BA was in a gallon pot and that it was very root bound when you purchased it. If you didn't tease the roots apart well enough that could be inhibiting it from acclimating as fast as the PS did even though the Polish Spirit was smaller to begin with.

Thirdly, although I often advise planting the largest clematis that you can purchase, often planting certain smaller clematis, especially ones as vigorous as PS, will get established faster in the native soil than a larger sized slower growing clematis.

As I see it, you have one of two choices. Leave the plants alone and see how the BA does this season. If it is still underperfoming this season, I would dig it up this fall, make sure the roots are still not in a tangled mess from its orginal potbound condition, if so remedy the situation as well as you can even if it means cutting off/breaking up the root bound ball, and then replanting it in the same hole. Insure that the plant is given good nutrition and moisture, and keep it well mulched and see how the BA does over the next few years.