First, philosophy is not a system. Some of its practitioners have been system builders, while others have merely been systematic without systematizing, but that rests on the individual. Philosophy itself is an academic discipline which aims at truth and understanding through argument and reason.
Now, anything can be done lazily, and philosophy is certainly no different. But clarity and rigor are typically valued in philosophical discourse, so an unsatisfying answer is often the result of a poorly framed question. It’s not philosophy that is imprecise, but rather the question “Which tastes better, mud or chocolate?” that is imprecise. Better to whom? I prefer chocolate to mud. So do most (all?) human beings. Does this make it better or just preferable relative to a certain subset of creatures with taste buds? The latter, it seems. Chocolate may very well be repulsive to some other subset of creatures.
Philosophy, then, helps us increase the precision of our questions. When it seems like the discipline itself is imprecise, it is because of the complexity of the questions themselves. Some things take a long time to clarify, and it hardly seems sensible to critique the discipline merely on account of it being more difficult than some others.
The article you link to is, unfortunately, ignorant of the actual progress of history. Yes, the sciences have spun off from philosophy once the discourse has settled on some empirical questions that would be relevant to the conversation, but those empirical questions do not mark the end of philosophy. We do still philosophize about biology. Indeed, science is rife with philosophical baggage that it often does not even recognize. The debates between Einstein and Minkowski on how to interpret relativity theory, for instance, are emblematic of this fact.
And finally, there are some areas where there may be no facts but where we still need answers. Science is typically useless in such circumstances, except at times when the odd empirical claim becomes relevant. Here the ability of philosophy to adjust to the context is invaluable. It’s status as “the most liberal of the liberal arts,” which is to say its flexibility and adaptability, make it quite suited for guiding institutions that can only work by changing over time.