Yes, there are positive aspects to the Knight. If you need someone to initiate and lead, he's your man. He's eager to take up challenges, passionate, and dives in headfirst. However, his enthusiasm is short-lived, and he may leave the details to the Knight of Pentacles.
In the context of feelings, the Knight represents short-lived enthusiasm before his attention shifts to other matters. The Knights can symbolize stages, with the Knight of Wands embodying the passionate, pre-courting phase, while the Knight of Cups signifies the dreamy, romantic courtship. The Knight of Pentacles brings loyalty essential for a relationship, and the Knight of Swords, on a mission, can be seen as the white knight in the RWS.