The significance of a right to sue letter from EEOC or DFEH is that you are allowed to file a lawsuit in court, as exhausting of administrative remedies (getting such a letter) is a pre-requisite to civil action.
Within itself, the right to sue letter has no bearing on the merits of your case. In other words, you may have a great case or no case at all and still get a letter as in most cases it is issued because EEOC / DFEH did not find sufficient evidence (or were too understaffed and overworked to deal with the issue) of unlawful conduct and they let you proceed with the case.
An attorney may get an immediate right to sue letter by filling out a form on-line as it is a pure formality.
Thanks, and if you have any questions, feel free to follow up.
California Employment Lawyer