A lining helps the straining of the fashion fabric a bit. In some cases, it seems to stabelize the structure some but I can sew and it beats me how. Not talking interlining, which is a second fabric sewn as one with the fashion fabric.
I took out a polyester lining underneath a full silk dress falling from a yoke and was much the happier for it.
If it's a straight dress, it might be better to replace with a full or half slip, like the taffeta ones that are/were made to keep knits from seating out. This would be more for cooler weather.