I reckon that the site should not be used for these types of question, not due to any inherent off-topicness of dua/wazifa/tawiz-seeking itself (I admit I know little about this practice or its place in Islam), rather because these questions typically do not come from any academic interest in the topic.
Rather than showing any intent to learn about Islam — even if only to learn enough to solve the problem themselves — questions of this ilk can basically be summed up as "I have a problem. Fix it for me." They are effectively the Islamic equivalent of Stack Overflow's "Plz email me teh codez."
Needless to say, "Plz email me teh codez" questions are not taken very well over there.
This is not to say that all such questions are inherently non-academic, just that the onus of proving an academic nature should be on the question itself. Expert answers to ones peers is one thing, where we can be reasonably assured that the questioner and intended audience have the required expertise and/or ability to judge an answer according to its merits, but just "prescribing" a solution to someone who's likely to follow it blindly without the ability to recognize its validity runs a significant risk of being actively harmful.
For much the same reason a doctor needs to be very careful providing medical advice, or a lawyer providing legal advice, or even a priest providing pastoral advice — and one should be very careful seeking such from random people on the internet — we should not be seen as a source for such "prescriptions." Unless the question is phrased in such a way that it (and subsequent answers) would serve an academic interest in Islam, it should probably be closed.