A Madrassa is established for the purpose of making people Allah-Wala (Allah-loving). In order to do that, one has to learn all those lessons those have been made mandatory in Shariah. From that point of view, undergoing lessons of both Ilm-i-Fiqh and Ilm-i-Tasawf are Fard (must).
It is possible to gain some knowledge on Ilm-i-Fiqh by studying at a Madrassa but learning Ilm-i-Tasawf is never possible without the guidance of a competent Murshid (path-finder). In early days, students used to complete their studies in the Madrassa and then engaged themselves in achieving Ilm-i-Tasawf by being bayat (being disciple) of a competent Murshid.
After the Madrassa were introduced here in this sub-continent, learners did not find the true Sohbat (companionship) of a true guide. Sadly, learners were not provided due encouragement also in this regard. Number of competent Murshid was few as well. It is easy to raise a huge building for a Madrassa and run few courses there but imparting knowledge on Tasawf shall not be easy until it is raised under the blessings of a true.