They wouldn't need parsers if they just made the damage based around a burst model instead of a sustained rotation model. FFXI didn't need parsers because the group either pulled off the skill chain or they didn't. It was visibly obvious when something was wrong. There are other ways to set up burst DD systems other than interweaving skill chains between players, and in all cases it becomes visibly obvious when someone is failing at their job. Combined with item level, that should be more than enough to invalidate most reasons for introducing a parser.

Plus, most people playing the game will not know how to properly interpret the results of a parser even if they had one. Designing the combat so they are not needed is the better solution.