High damage to gain:
Use high attack speed if you using flintlock, 5000 weapon damage especially because flintlock has lower base damage which is compensated by WD and attack speed/APS.
I'd say remove Nadroji and use a different amulet . Also remove fauns gift.
Since flintlock is primary skill, using 4 Multi attack and 4 Extra Attack is vital as well as 20+ hero points in flintlock and even the skilled mythic. Then 1× Push the Limit to further raise the Mainhand % of flintlock. Of course using Mutilate Talent is must have on rogue if you have Multi and Extra Attack.
You'd get 2000% MH damage of Flintlock and you have multiple bullets+ fast attack speed ftw.
Then use Glasscannon 50% or even Barbarian or both. If you use barbarian, one mana affix or so will be needed to compensate but it's worth the huge damage boost.
Use this build but Frozen explosions or Fire build or even poison build.
All ice , Frozen Set, use Crushing Blow 30% , deadeye affix. If you have deadrge affix , remove 30% deadly strike and replace that with the 30% crushing blow to do well in high floor farmings as crushing blow goes great with high attack speed flintlock and the explosions could be kept.
Maybe Epiphany bonus could get used if you wanted epiphany part of the farm build which is simple to achieve.
Keep the farm affixes though and you have hirling as well to help with farming by putting luck on hirling and item drops.
Another good set to use is Demonic to go with Relentless Talent or as an alternative to Relentless when he uses rebound. Or adventurer to go with momentum.
Obviously he uses stealth but add dodge crystal affix 30% and some power 299 since stealth has changed to require 50% dodge for 100% dodging since it doubles current dodge and it goes without saying that stealth 20 hero points is must have.
However momentum + Demonic would be even better in terms of damage and goes great with crushing blow and especially if you ended up using Relentless instead of rebound for whatever strange reason.
Maybe even add 90% weaken if you don't want ignore resist but ignore resist can be ok.
Many more to be said but it's up to you to see how you can improve the build.
This build was made a while ago but good thing it can improve a bit. Also not much need for more than 400% explosive. 400% is enough tbh.