I did the Crota ones at 29, with 2/3 legendary armor, and HoW... Maybe at the same level. The exotic helmet moved me directly to 32.
- In the warmind, the initial problem was that I thought waves would keep coming unless I killed the wizards and tried to kill them without getting rid of the mininions. After understanding that it was easier. Biggest issue was the vestiges taking out your safe spots.
- With the Urn, I could not find a safe spot to heal and kill from behind cover. I would have to hover hoping I would not get shot. I believe that one practically has no safe areas, and thralls will force you to move. I only had an scout rifle and it was not enough rate to kill them.
- The last story fight about skolas, I would get swarmed immediately while trying to kill the Servitors before the waves came. Skolas coming for me plus captains with shields. Since my best weapons at the moment were a legendary scout rifle and the murmur, I barely could do anything. I went down one level, but I would get fallens even from behind. In the end I found that retreating to the farthest part, very few enemies would come down and Skolas could not move beyond a point, making him an easy target moving around a column.
Usually I play it safe when soloing on hard with the heroic, but some missions don't have a safe area and enemies will make a run for you instead of keeping the distance with firearms. Thralls in heroic can be the worst in terms of invading your safe place. No other enemies except for blade fallens can be so moronic in making it so personal and close quarters.
Overall, I am still having issues with weaponry. I have a decent scout and pulse for PvE, and I got the low grade humillity sniper, but I am really missing a shotgun and a rocket launcher, making bosses extremely hard to kill.