The real ethical issue here is that such defense attorneys must always keep in mind that their first duty is to their client, not to their own career. Therefore, the dilemma is not really an ethical one. It is more a dilemma of personal discipline and integrity -- does the lawyer have the moral fiber to put the client's interests first?
The struggle here comes when acting in the client's interests would not promote the attorney's career. For example, if an attorney knew that a guilty plea would be best for the client, he or she should pursue that plea even if it would not help the attorney's career.
This is not really an ethical dilemma in the sense that there are not two sides to it. The ethical duty is clear, what is difficult is having the moral courage to follow it.
I see no ethical dilemma in defence attorney's or anyone else merely using high profile case for to make name for themselves. Neither representing a client in a high profile case, nor trying to make name for oneself is unethical. I don't see any reason why the mere combination of high profile case and making name for oneself becomes unethical.
It is unethical to use dishonest and unprofessional practices in any case - high profile or low profile. Similarly it is unethical to use dishonest and unprofessional practices for any purpose. People may use unethical practices for gain many different things like name, money, safety, and power. There is nothing inherently wrong or unethical in pursuing any of these objectives. Only the methods used are ethical or unethical.
I fully agree with the point made in the answer posted above that:
... their (defence attorneys) first duty is to their client, not to their own career.
But this does not mean that it is immoral for an attorney to be choosy in accepting choosing clients or briefs. Once the attorney accepts a client, he or she must act in the best legal interests of the client. But an attorney is not obliged to accept each and every case offered. He or she cannot be considered to be acting unethically just for trying to seek and accept cases selectively in the interest of a better career. For more information on the duties of attorneys wee the website linked below.