Healing is more of an art than a science, and there are multiple ways to achieve victory. Factors such as raid comp, coordination of healing CDs and Strat will affect meters greatly. Bottom line, if your raid isn’t dyeing to something you could have prevented as a healer then there is only so much room for improvement as you end up competing against other healers for a bigger slice of the pie.
Looking at your logs your not in a bad place, your Item level is a bit low so that’s going to impact HPS. I’m no expert myself but a few things I noticed, you have the earthen shield talent but only used it once on your last attempt and not at all on the first. Ill agree it shouldn’t be used on CD, but for a fight like skorpyron its should be a lot closer to 100% uptime. I used mine 5 times over a 6 min fight last night on Scorpion and I average about 2.4M absorb per cast. also your healing rain cast count seems a bit low and your HT overheal % is pretty high.
I’m a big fan of using all my healing spells and using them when most necessary. I think your on the right track and once you get more gear and some of the healing legendries, you should see a nice improvement. as far as stats go I felt good with Crit >34%, mastery > 100% and haste >15%. Iv been finding it harder to achieve these numbers since 7.1.5 since EVERTHING seems to have versatility on it now.
anyway ill post my Logs from last night, feel free to compare. https://www.warcraftlogs.com/reports/qYpTHAWbQhxDVd7F/#type=healing&fight=4