Career in Expat Tax

Hello, I recently left one of the big four after about three years in their specialized expatriate tax group. I left for one of the top national firms in the Midwest to pursue experience in other areas of tax I was never exposed to during my B4 tenure. However, after a few months I've come to the realization that perhaps I really did enjoy what I was doing with my previous firm. Before I make the call to go back, I just feel like I need more general exposure to all realms of tax before I choose to commit to such a specialized group in the long run. My fear is that if I do go back to my previous firm and choose not to pursue PPD, it would be difficult to go into industry or find another job as I would be limited to just expat tax. Has anyone ever come across this in their career or dealt with a similar situation? Thanks, Bull&Bear