ES3 only works if you're in a pre made team. Otherwise you cant count on anyone healing you. And that 1 and only Cmdr. slot isnt helping you when you get focused.
I run a pretty basic set up that has been working great in PvP "non pre mades" and is pretty boring in PvE. I'm in a Vorcha but works for any cruiser.
2 beam banks, 1 array, 1 torp
3 arrays, 1 torp
Tac team 1, delta 1
high yield 1
Power 2 Aux1, Power 2 Aux2, Eng team 3, Aux2Sif 3
Power 2 Shields 1, Power 2 shields 2, Eng team 3
Hazard 1, Transfer shields 2
This, I think, is pretty basic. I can keep my shields and aux up at all times. Letting me have a strong Aux2Sif 3, HE and Tss. While still allowing for 100 power to weapons.
I can throw a Tac team/Tss 2 on a teammate and an Aux2Sif3. Giving them good shields and good hull + resist. If needed, delta 1. Then 15 seconds and they get Aux2Sif3 and Eng team 3. All of these heals are strong and able to use on a teammate, or if I get focused, myself. The only hole here is SNB since I have no Sci team. But surprisingly it's not a huge deal, you can wait that 20 or so seconds.
So. Why beams. Well my job isn't to kill things. It's to support my team. Those BoPs need all the help they can get right?
If however the OP is not planing on doing any PvP. Then load up on Dual heavy cannons, turrets. Make use of rapid fire/scatter volley, Aux2Damp. and Power to engines 1 and 1.