Lets look at a much simpler, and more realistic example. Your ability costs 30 energy, is a 1 sec GCD, and hits for 750. To make this easy lets say you have done your first 2 rotations and are now sitting at 10 energy. At 20 energy regen per second it will take 1 second to regen the 20 energy needed to have sufficient energy to do your attack again. You hit 30 energy and do your attack. Since your attack is on a 1 sec GCD, and since energy regens through the GCD, by the time your attack ends you are at 20 energy, 10 less than needed to do another attack. You now need to wait 0.5 seconds to do another attack and after such, are stuck in a cycle of needing to wait 1.5 seconds before you can do an attack.
Since your attack only hits for 750, you are producing 500 DPS. Lets say your finisher hits for 1,500. It will take you 1.5 seconds per combo point, or 7.5 seconds, to generate 5 combo points. At 500 damage per attack (per 1.5 second), plus the finisher (for arguments sake, lets assume it also is a 1 sec GCD and only costs 30 energy), it will take you 9 seconds to build 5 combo points and deliver a finisher. Your total damage would be 5,250 and your DPS would be 583 DPS.
Because of the energy regen issue, the rogue attacks (which are mostly on the 1 sec GCD) have in effect become the same as the warrior attacks (which are also on a 1.5 sec GCD) when measured as number of attacks per second. The difference is that warrior attacks hit much harder per attack (to compensate for being on a 1.5 sec GCD), benefit from the spike damage from a finisher once every 4.5 seconds (versus once every 7.5 seconds for the rogue), and because of the 1.5 seconds global cooldown and because many warrior attacks are not on the GCD, warriors are able to manage their energy more efficiently.
Because of the energy limitations rogues must deal with they have by default become watered down warriors who have weaker hits per every 1.5 seconds. I'm astounded no one at Trion has figured out this simple problem with their game design.