I don't have a PhD/MD/or PharmD, can I still become an MSL?
Yes you can, but it depends on the country. It is worth noting that hiring managers have more and more candidates to choose from. Therefore, there is a trend of hiring more candidates with a terminal D degree. However, in a several countries they value pharma industry experience more than just your degree and are therefore more than happy to hire people with Bachelor or Master degrees into the MSL role.
In our opinion, moving forward, the scientific complexity of clinical trial design and the increasing use of biomarkers will push recruiters to employ candidate with highly specialized scientific expertise, if this is obtained via a terminal D degree or via other means doesn't matter. As long as you are a subject matter expert.