If everyone does not like the current setup, why not just add a third property to each Overclocker mod.
Call it a "stacking inefficiency" make it grow expotentially, rather than multiplicatively like the bonuses. The more OC's you add the less effective the lot becomes (both less speed AND more powah). Tune to liking. Problem solved.
I would still like to see tiered OC mods. Higher tiers have better efficiencies and lower stacking penalties (if introduced). Stacking would introduce some fun non-linearities, and would definately make higher tiers much more useful.
Tier 1 OC's: 1.5x EU/t
Teir 2: 1.45x
Teir 3: 1.4x
Finally, any change we can get tiered energy storage mods too? It would be nice to be able to condense all of my Energy Storage into 1 block.
Tier 2: 10k EU
Teir 3: 100k EU
Tier 4: 1M EU