Am I the ONLY person who plays this game and values Power Efficiency Mods?
Power Amps are only good on things that use direct damage powers, like flamers, grenades, and Slayer.
Power Efficiency Mods allow for faster explosions (the bulk of damage for many classes) or to take a heavier weapon (something I often find myself doing).
Putting a Power Amp on something like a Paladin, or Human Adept/Sentinel/Engineer is pretty ineffective in improving overall DPS as the bulk of your damage comes from explosions. However, throwing on a Power Efficiency Mod and a heavier weapon will impact your overall DPS by improving gun damage output and/or faster explosions.
Power Efficiency Mods allow you to turn a power spammer, into a hybrid one-(wo)man army.
Of course, grenade kits and weapons platforms benefit more from Power Amps and Adrenaline Mods (respectively).
Cyclonics, for the most part, teach bad habits like standing out in the open and getting shot. Shield Power Cells (as all shield recharge speed) can get you into trouble due to lack of interaction with shield gate. However, a full shield recharge batarian can keep their shield number high enough to mostly negate this issue, so there are exceptions.
Platinum is much more about damage output than survivability, which is why offensive armour mods and powerful characters (like the Fury) do much better than tanky characters (like the Juggernaut). I say this as a whole-hearted lover of a GOOD Juggernaut, a great character for Gold, but I would take almost any other character for Platinum.