I think commendations are fine, but the mentor requirement for 1500 makes no sense. It only exists to delay meeting the requirements.
If you play well and don't do anything that might annoy people you'll get the comms eventually. I've heard the advice to play healer before but I'm sure most of the mine are from DPS. You will be at the whims of the rest of the party though. Some days you will get many and some days you'll get none, even if you carry a group. Try to top DPS on DPS classes and use your party mitigations. On healer use rescues (only if it will help) and keep low HP/vuln stack players alive and res quickly if people die. On tank use your party defense tools and external heals on players that take hits.
