Shaman's Wind Shear costs 8% base mana, is also off GCD and has a 6 seconds cooldown. Enhancement has no mana problem throughout fights because of mana regenerating mechanics - therefore there is no limiting factor to interrupting.
Paladin's Rebuke costs 10% base mana, is also off GCD and has a 10 seconds cooldown. Ret has no mana problem throughout fights because of mana regenerating mechanics - therefore there is no limiting factor to interrupting.
DK's Mind Freeze costs 20 runic power (hey starting to be on par with Kick?), but DKs also have a talent, Endless Winter, which reduces the cost by 20. DK's interrupt are also free, therefore there is no limiting factor to interrupting.
Warrior's Pummel costs 10 rage, but just like DKs, warriors have an arms talent, Drums of War, which reduces its cost and the costs of shout by 100%. therefore there is no limiting factor to interrupting. If this talent isn't chose, the fury talent, Rude Interruption, doesn't reduce the cost, but increases warrior's damage by 5% if a spell is successfully interrupted.
Now, I think you get the point. Pre-cataclysm, It was easier to kick due to high energy regen (17/sec with 60% or higher crit) and using 15 energy on a kick wasn't such a big deal.
With the current state of the rogue class (read: they are energy starving like an university student without his coffee), using 15 energy to kick right away like the other classes can isn't quite possible for the rogue class.
Using 15 energy every 10 seconds to interrupt on a raid encounter like the Omnitron Defense System also gives up ALOT of energy, and indirectly, ALOT of DPS. Basic maths:
15 energy * 6 times per minutes = 90 energy
90 energy * 7 minutes average fight (for the sake of easy maths) = 630 energy
630 energy / 35 energy (envenom) = 18 missed envenoms.
Obviously the maths are skewed because I didn't take into account combo points generating with mutilate, but it just goes to show how HUGE it is for a rogue to use interrupt on CD compared to the other classes. Hopefully the devs will put some thought into it.
Cliff notes: Unlike other classes, rogues can't kick ASAP due to energy starvation, and the cost of kick used on CD makes the rogue class give up too much DPS compared to other classes.