You do not need to run a generator. You can use the slot for something more useful. You can get unlimited energy even without using inner sight.
There are many ways to regenerate energy for rogue’s. There are skills/glyphs/CD reduction/Energy rudction/Energy regeneration.
Veterans from D3 knew that the most broken builds were generator less builds. Blizzard hates these builds. They even just mentioned it in the dev stream. They wont be able to nerf all the things that make unlimted resource possible. They already screwed up.
Here is the core base of the build I am currently running. I am even running one of the most considered crap skills for rogue (concealment) but it will all make sense. I say core base because this build is extremely versatile. You can run it with any resource spenders you want.
Ill start with the biggest generators.
Shadow imbuement passive consuming shadows. 30 energy per enemy killed with shadow.
Aftermath ultimate passive. After using ultimate generate 75 energy.
Innervation ultimate passive 8 energy on lucky hits.
Concealment you gain 40 energy when entering stealth.
Momemtum…Everyone will end up running momemtum. Not only does it give dmg reduction/move speed it gives 30% energy regen. Add on the Healing momemtum aspect which is extremely strong. 200 health per second for each stack of momentum. 600 health regen per second during combat.
Energy regen. 30% from momentum.
Adrenaline rush 15% while moving.
Aspect. Killing a vulerable enermy grants 50-70% energy regen. For 4 seconds. In combat this is 100% uptime.
items
Energy cost reduction/CDR/Max energy.
Mothers embrace aspect if core skill hits 5 enemys 40% of cost is refunded.
Energy reduction affix’s 30% from items boots/amulets.
CDR 30%
Combat glyph. Core Skills that crit restore 12% of their energy cost.
Max energy 140 energy +20 from 2 items.
IMPORTANT ASPECT. Rare find. “your shadow clones mimic your imbuements” This aspect is critical to the build as your shadow clone is off producing energy for you constantly. Rare find because it only comes on items no codex and even harder to find the ancestrial version.
Slap all these together and you have unlimited energy CD’s any time you want. Because of the unlimited energy your Ult CD is always up. Your ult gives you 75 energy every time you pop it.
You need to use your CDs correctly always keep in mind your ULT resets all your other CD’s…So you can use conceal for a quick 80 energy if used before and after your ult.
Just running around in combat you are sitting at 100% energy regen. Your core skill of choice should only cost you about 20 energy and mostly being cast for free due to refunds and passive energy regen.
At level 90 I have never run out of energy. I started this build around level 40 and it only snowballs as you level. You get more and more energy options. At this point I no longer am looking for energy stuff or CDR you will start to look for attack speed to spend your unlimited energy.
In the super rare instances you run out of energy (world bosses) (4 man groups) you simply pop your conceal ult combo and gain 200 energy at any time you wish.
Throw a resource potion on top of all of this and its just overkill.
TIP tho for nightmare dungeons. Salvage the resource burn affixs for sure.
In closing its easy to get unlimited energy/ults/cds just look into the game. Once you start stacking everything together its easily done.