Lack of organization, procrastination on deadlines and limited multi-tasking abilities are options for an interview weakness, but the best answer is one that steers clear of qualifications important to the job. Using lack of organization makes more sense for a creative position than an office administration role, for instance.
A good strategy is to identify the non-impacting weakness in a subtle way, and then identify ways the candidate has demonstrated growth. A candidate might say, "Since my field is largely creative and deadlines aren't as pressing, I've struggled with deadlines in the past. However, I have gotten better at keeping a detailed schedule now that I take on more deadline-oriented work."