Neither of those talents resulted in a significant DPS increase nor impacted gameplay.
Umbral Blaze is such an underpowered and unenjoyable talent that its inclusion in the Demo talent tree from the outset feels almost insulting. My suggestion for addressing two issues simultaneously is to keep the talent where it is but add an additional effect.
Bilescourge Bombers have a 100% to apply a stack of umbral blaze on the target
With this adjustment, Umbral Blaze will maintain its relatively low damage; however, warlocks will now have a guaranteed method to apply it. Additionally, warlocks will at last possess a damage-over-time effect that integrates with the Demonology toolkit and is compatible with the Wicked Maw talent.
Another fix that needs to be applied to Bilescourge bombers is to make it work with the Tyrant - the 15% damage increase. Because right now bilescourge bombers do not gain damage increase during the uptime of Tyrant. And there is a thing: Bilescourge bombers is a warlock spell, it is not a summoned pet, despite it’s VFX, and this ability only scales from mastery. But it’s visual language clearly tells us that we summon a swarm of demonic bats from the nether, and it would be only logical for them to scale from all demon damage increase modifiers.
And last but not least, Pact of the Imp mother.
The 15% chance to copy the hand of Gul’Dan sounds cool on paper but in game you barely see it’s effect, not to mention that because we always try to maximize HoG using 3 shards the frequency of HoG is not that high, especially on the move or PvP. Insead of that we need something to make HoG and Wild Imps more effective. I have two ideas.
1 - Pact of the Imp Mother empowers Hand of Gul’Dan, wild imps now can cast their fel fire bolt on the move and their range increased by 10yd.
2 - Pact of the Imp Mother empowers Hand of Gul’Dan: consuming a demonic core reduces the cast time of your next hand of Gul’Dan by 33% and summons an additional Imp, stacks 3 times.