There are a few key DPS upgrades to grab in the main class tree, such as Overflowing Energy as well as the Crit and Haste buffs Tome of Rhonin and Antonidas. Besides these, your path through the tree can vary greatly, picking up defensives or utility as needed.
The only real letdown of the class tree is our capstones, with all of them besides Temporal Warp (The double lust legendary effect) being quite underwhelming. I would recommend going for the Shifting Power and TW capstones in every scenario except boss fights where your guild does not bloodlust until the end of an encounter. In that case, swap Temporal Warp for Time Anomaly.
There will not be any variation between a ST or Cleave setup with fire.
Once you get the new 10.2 tier set, we drop Fire Starter and Phoenix Flames talent for Controlled Destruction and 1 point in Flame Accelerant
Mythic+ and AoE
Disclaimer: Drafted before Patch 10.2 release, so this build is subject to change
Unfortunately, Ignite has received multiple nerfs during the PTR of patch 10.1.5 and some talents also has been redesigned to work less around ignite since it seems Blizzard doesn’t like ignite gameplay on AoE. We are most likely coming back to Flamestrike on Mass AoE, which is around 8 or more Targets.
Flamestrike now contributes towards Hot Streak with our new talent, Fuel the Fire. It's supposed to be a much smoother gameplay, since we have more room to play around Hot Streaks procs with Flamestrike.
This build is focused towards a lower target count in M+ and raid with some adds
Keep in mind the ignite build is require ramp time, which means you need to build ignite on a Priority mob or a Boss and cleave off him with Ignite. It can be used in lower target count up to 5 mobs, after that the Flamestrike build pulling ahead in terms of damage.