Listen.... I would be fine with 5 second recycle time or 10 recycle time... I honestly don't care as long as the damage isn't nerfed as well. As is mentioned, WoTs has a heck of a lot longer recycle times and they have a /single/ weapon and the game works fine.
But if you have 10 weapons, you can have a shot a second and your only limiting factor is Heat... as it /should/ be. If you increase the recycle time, someone with a mech with 10 weapons (I am pretty sure there is a Hunchback with 8 Med Lasers for example) your not even using half of your lasers and still producing a non-stop stream of fire. You start getting into that dangerous area of halving damage and dealing with fractions, and you also start messing with heat. Reduced damage over a 5 second span also means your not hitting the same spot you were hitting 5 seconds ago unless both you and your target are not moving. This means now that yeah... an AC 20 isn't a threat to a mech, and that your honestly better off with a AC 10 or multiple Medium Lasers because it is the same packets of damage hitting. All your doing now is shooting...pellets. The weapon is nerfed.
I think the real people it effects with a 10 second recycle time are the mechs with 1 main weapon, something like a Stinger or Wasp (for example). With the heat sinks they have, there should never be an issue of overheating with a stock mech. With one main gun faster would be better, but if it means the damage is halved... you know what, I would take the 10 second recycle time for the full 5pts of damage.
End of the day, /this is/ what Beta is for, to fine tune this. The Devs are playing it now, but what they are playing may not what we will be playing in beta, just as what we play in beta may not be what is played on release.
I see no reason to speed up cycle times at the expense of damage or to decrease heat per shot. Just track heat and ammo strictly, don't increase the effectiveness of heat sinks (still just one points per 10s) and make the risk and consequences of overheating a serious deterrent - ammo explosions should be a very real and present danger, and should in most cases force a pilot ejection, and running hot should inflict significant movement and accuracy penalties.
Using something like this, and considering my example of the Hunchback above, the first volley would push the heat level up to 14 inflicting a penalty to movement and accuracy, and it would only have dropped to 10 by the time of the next small laser shot. When medium lasers would be ready to fire again at the five second mark, the heat levels would still be at 8, and the movement penalty would have decreased, though a small movement and accuracy penalties would remain. At the 7.5s mark, when the AC/20 would be ready to fire a second shot, the heat level would be back to 12, with the movement penalty slightly increased, and the accuracy penalty holding steady. The resulting heat build-up would risk a shutdown, and a slight chance of an ammo explosion, and next laser shot at the 10s mark would come at a significant penalty, as the 'mech would have a heat level of 17 and not only would accuracy and movement be impaired, the pilot would be suffering some distraction as well. That would push the heat to 24, incurring a substantial risk of shutdown, and doubling the chances of an ammo explosion. By the time we hit the 15s mark, and the next chance for an alpha strike comes around, the 'mech is back to 17 or 18, there are significant penalties to movement and accuracy, the pilot is slightly impaired, and firing that massive blast is going to push the heat up to at least 31 - forcing a shutdown, and seriously risking ammunition explosions and pilot injury.
At this point, the Hunchback pilot is pretty well hosed, and has probably spread or wasted a lot of shots due to penalties, and an opponent who watched their heat gauge instead of trying to cram out 121 damage in 15s may well be in a position to capitalize on the recklessness of his foe. Also consider that in the first 10s of combat, the more aggressive pilot put out 85 damage while risking shutdowns at least three times and ammo explosions twice, while a more conservative pilot could have still dished out 63-66 damage without suffering more than minor penalties to accuracy.
As for ballistics balance, an AC/10 is still going to do just 30 damage in the time a AC/20 does 40, and both are pretty similar weapon systems. Trying to use energy weapons in the same fashion as ballistics would lead to much higher heat build-up, forcing energy boats to either delay/chain fire their weapons, or spend significant periods of time with minimal offensive capabilities while they try to get their temperature back into a manageable range.