The debate between 2p vs 4p rogue is depends on two factors, first one is spec and second one RNG.
2p set favours both spec rupture and evi while 4p favours evi more than rupture.
And now second factor is RNG. With 4pc set you are playin with rng alot, its just like ret pala divine storms rng. If you get good rng you will outperform if not it will be similar to 2pc.
Tho 4pc imo aint that ideal to play for halion or LOD, due to various factors. If you want i can shred light on those.
But all in all it vary from player to player on their playstyle. Some would go with 2pc nd some would with 4pc. The difference between them aint that much that you would go for specific set.
There is an important stat difference between sets, since you will have lot less hit and much more crit thats not benefiting you as much for aoe, and you will lack energy regen. But Im not gonna enlighten you guys lol.

If your Ip does less dmg you prob didnt stack 5deadlies before Ksing, not nerfed im any case.