If motivation consists only of drive-reduction, what is the perfect state of a human being?

I don't perceive any "prefect state" for humans, but you might be thinking of a state of homeostasis.

Motivation is a complex and multi-faceted aspect of human behavior. While drive-reduction theory recognizes the role of fulfilling physiological needs in motivation, it does not account for the full range of human motivations and desires. According to the drive-reduction theory, the perfect state of a human being would imply the absence of any needs or desires, meaning all physiological drives have been satisfied.

However, it is important to note that motivation goes beyond just drive reduction. There are various other motivational theories that recognize additional factors influencing human behavior, such as Maslow's hierarchy of needs, self-determination theory, and cognitive theories of motivation.

Maslow's hierarchy of needs suggests that humans have a hierarchy of needs ranging from basic physiological needs to higher-level needs, such as self-actualization and self-esteem. According to this theory, the perfect state of a human being would involve the fulfillment of all their physiological, safety, love/belonging, esteem, and self-actualization needs.

To understand the perfect state of a human being from a motivational perspective, one should consider multiple theories and factors that influence human motivation. It is important to acknowledge that there may not be a single, universally agreed-upon definition of the perfect state, as individual desires, values, and goals play a significant role in shaping human motivation.