I think that was the last season I watched. I really had zero interest in Equestria Girls, plus s3 wasn't all that important to me. It was long enough ago that I don't remember why, but it was enough that mlp-obsessed middle school me never went back to finish the show. I think I enjoyed Sombra, but I don't remember caring enough to follow the Crystal Empire plot. I even remember not really caring when Twilight became an alicorn. (Though EG was probably the main reason because I thought it was going to affect future plots and worldbuilding.)