Here's the thing. If they would plan to increase level cap by lets say atleast 10 leves a year and add appropriate content it would not be that bad. They could add 1 great item per HNM and still keep other content relative if done properly.
XI was at 75 cap for so long, when they raised the cap everyone screamed bloody murder but if they do it once a year people will know what to expect. Also, it will help them to see what is the most popular type of content and develop content accordingly.