Looking at my school personally (University of Georgia) there is absolutely no reason to get your MLA if you already have your BLA. It is essentially a sped up version of the BLA, where you take most of the same design studios just with masters students, and you work on very similar projects. If other schools are similar you really wont learn anything “new” just spend a few more years re-doing projects so yes the experience and practice is nice but there are better options in my opinion. If you are going to do something I would take the idea of Kevin and find a related field, personally after I finish my BLA (im in my 3rd of 5 years) I am looking closely into the Master program for Planning that they are introducing next fall here at UGA.