It's difficult to see many qualities that one can admire in Wily from Act I. I think that we see that we have to admire the fact that Wily seeks out success. It will come to be a part of his character that helps to cause his downfall later on in the play, but in the opening act, we have an understanding about how he views success. Wily believes in it and transmits these values to his family. Another quality we see in Wily is that he is not lazy. He does work and he works with a strong ethic. His travels to other places, the fact that he still is fighting for success, are all admirable qualities. Granted we will learn that Wily is fundamentally unhappy, but in the opening act we see him as a character who is struggling against the matrix of odds placed against him and struggling to "make it." In a very admirable way, we see that Wily possesses the power of memory, something that allows him to transcend the difficult times that envelop him and see something else that can allow him to transform, at least from a mental point of view, his condition. This can be seen as an admirable qualitiy in his character.
I agree that Willy does come out quite strong revealing himself as a troubled person. However, we do sense his attachment to Linda as his source of strength; his anchor. We also feel actually a bit sorry for him. It is obvious that he has his thoughts all over the place and is not being quite himself. He seems anxious straight from the start, and may cause the audience a sense of uneasiness. I would say the close connection between himself and his wife is touching because it reflects a scene from a conventional and seemingly solid American marriage in which man and wife are supposed to stick by each other through thick and thin. Arguably, however, this could be about the one thing aside from his love for his boys, that we can find likeable about Willy.