Hello there Zurtra!
It took a while to get back to you. Hopefully late but not least. Analyzing heroic and normal logs is different from mythic indeed. But no worries, I’m sure we can give you a few pointers to help you on your way.
I started with checking on your battle.net profile. There’s a few things standing out to me. First of all, your gear seems poorly itemized. Not strange, when you are gearing your character. But it will affect your output. Most equally geared resto shamans you will run into (and other healers), can have the capacity to out heal you if they are better itemized for their level. Initially there were some enchants missing, but you fixed those before I could send out this reply :P.
You posted two logs. One were you felt you did ok, and one where you felt like you did awful. It happens to be that the first fight (Gorefiend) has great potential for a resto shaman, while the second fight you linked (Assault) can even make a disc priest cry.
That said, let’s check a few basic pointers. What does your general spell weave look like (any abnormalities)? Are you using Riptide, Healing Stream Totem, and (to some extent) Elemental Blast on cooldown? Are you making use of your Healing Tide and Ascendance?
One thing standing out to me on your assault kill, is how high Healing Rain scores in comparison to Riptide (same goes for the other shaman on that kill btw). Healing Rain, currently, is a not so powerful spell at a rather high mana cost. Riptide, on the other hand, is precious regarding your output. Riptide has a 5 second cooldown. On a 6.26-minute-fight duration (386 seconds) you can cast (386/5) 77.2 riptides. You casted 32 (32/77), which is roughly 42% of the maximum possible number of casts. Riptide lets your chain heal bounce better (hello high tide talent), not to mention with the class trinket you’re using: it will actually spread/proc more riptides!
Your healing stream totem uptime looks neat. I can’t make too many remarks on your mana since advanced combat logging was turned off.
Then I arrived at the cooldown section. You didn’t use any cooldowns? Neither did the other shammy. Given that shammies are cooldown heavy, that is quite something you’re missing out on (healing tide and ascendance to begin with).
So for your assault log: riptide more (on cooldown) and use your cooldowns my friend (could have probably used them twice in this fight).
For your gorefiend log. Let’s check the same things. Healing stream uptime got a bit slacky this time 5 casts on a 5.30 minute fight (330 sec fight /30 sec cd= 11), (5 casts /11) is a 45% uptime.
Riptide, 29 casts (330 sec fight / 5 sec cd = 66), (29/66) is a 44% uptime.
Mana: you were oom for half of the fight (or close to oom). You can battle that with casting Elemental Blast on cooldown (increasing your spirit). You casted 15 blasts (330 sec fight / 12 sec cd = 27.5), (15/27) is an uptime of 55% so there is much to be gained here. You can also consume mana potions (either the instant ones or the channeled ones), you used neither.
You used healing tide, twice even (in both feasts). Nothing to comment on that, good usage. Just make sure to use it every fight. Ascendance however is nowhere to be found. This is a perfectly good cooldown going to waste. Especially on a fight like gorefiend. Use it in the feast. Just follow healing tide up with this cooldown. When ascendance is up, cast as many chain heals as you can and you should be golden.
To conclude your logs: stick to your spellweave and don’t get distracted (cast riptide and healing stream on cooldown – and elemental blast somewhat as well). Fill it up with chain heals (alternated with healing surges/healing waves) and only put down healing rain when most of the team is stacked up. Preplan your cooldowns (both healing tide and ascendance), and make sure to use them.
I want to recommend two articles from our website to you. The first being our ‘rotation’ page: https://chainheal.com/spells-and-their-uses/. Here we explain in detail what the trade-off is between casting which spell at what time. Additionally, I want to point our cooldown article with you (https://chainheal.com/healing-skills-3-becoming-a-cooldown-canon/). Mind you that this article is written from a sniping priority mind set, which is not applicable when progressing and gearing. However, the tips and tricks mentioned there will help you figuring out how to fit in your cooldowns. And explain what the options are.
I hope this was helpful to you. If I screwed my math up somewhere, or misread the numbers on the logs let me know… I tend to derp on these things and I didn’t have my checker available (Keehn was without internet :D).