I agree about consolidating too many fixes, and that's why we take it on a patch by patch basis. Some patches may list out more than others, or we may include multiple notes of consolidation around different areas to ensure that the work done is given credit.
Since part of the issue is that lumping hides the magnitude of the work done & changes made, I suggest that you include a counter. So perhaps say, "Fixed 2+ environmental issues on Ilum" or "Corrected a total of 15+ clipping issues on Tatooine, Belsavis, Balmorra, and Coruscant." The "+" gives you leeway to not be pedantically correct while still sharing the magnitude of the effort and changes made.