Update: I'm at the moment leveling WHM. I got into anti-tower dungeon (lvl 60) and everyone was sync cap geared. I literally may have used 5 healing abilities (OGCD/GCD) throughout the whole dungeon, We may have been fine if I didn't use those 5, so beside maybe the holy stun I was of literally no more use than the dps, and I had gameplay wise nothing to do besides spamming 1 ability throughout the whole dungeon. Many other dungeons I've done so far also required minimal healing, but it was just so obvious in this run I was almost redundant.
Now obviously jobs shouldn't be adjusted for older content, but from what I hear from all of you is that it doesn't get much better, not even in high end content if nobody makes mistakes. It just makes 0 sense to me why healers don't have a more complex dps rotation, like at least 2 dots or something. As I'm leveling, I feel like tanks use more damage mitigation OGCD than healers have to do anything healing related, yet tanks have an engaging and far more complex dps rotation. Makes no sense.
My favorite runs so far have been those chaos runs in which tank & dps don't know what they're doing and get damaged all the time due to mechanics. I think I wouldn't even tell a tank he/she doesn't have tank stance on cause it would make for a more interesting instance lol. I don't even care much about finishing the dungeon asap, just want to be more engaged. It doesn't seem good design to me if you'd rather have a bad party for the sake of engagement, although arguably that will be more enjoyable for some people no matter the job.
Now I'm not a healer main so I don't want to speak out of my place but I think healer role would be great fun if it had a complex dps rotation similar to tanks or maybe little less while still having to heal from time to time just like it is now. If this were the case I think I'd even switch to a healer to healer job as main. The idea of dealing with complex dps rotation and timing your heals at right time sounds very appealing to me. It would also make the role more fun for people who are leveling them and/or are going through older content. Since most content is already designed the way it is, I feel like it would perhaps be the best solution. Healers could then basically become dps classes who heal from time to time (which seems to already be the case), maybe attracting some of the dps crowd.