I think there is need to remind situation that was several months ago. Patch 5.031 Harvest Of The Unloved (Released March 21st, 2012) made strong buff towards harvesters because many players "pointed out the fact that harvester upgrades were basically just universally inferior (with some small exception) to econ station upgrades".
I will quote patches notes about harversers changed
Knowledge cost from 4000 => 2500 (so 4500 total).
Production from 36 => 73 (so +16 => +53).
Yes, that's a lot, but that's what parity with econ III looks like. And nerfing econ III would have been an outrage considering how much waiting-for-resources happens on challenging games _with_ econ IIIs.
In short, harvester upgrades should now be competitive with econ station upgrades. Getting mkIII in both harvesters also now costs the same amount of knowledge as getting mkIII econ stations, but has a somewhat lower "barrier to entry" in that the individual knowledge costs are smaller.
Further balance feedback is, of course, welcome. This change will have a fairly dramatic impact in favor of harvesters on multi-HW games, for one, but it's primarily important that choices be interesting in single-HW games and adjustments can be made for the less common scenarios (as long as multi-HW doesn't become excruciating, of course). Of more concern is the impact on multiplayer games if all players gift all their harvesters to one player who upgrades to mkIII harvesters (and gives resources back) and other such tomfoolery, but that can also be adjusted for as the need arises.
I guess such feedback was given now. If after such buff harvesters outshine economic stations that means some changes to harvesters shall be reverted.
I still think my idea of allowing Economic Orbitals increase your resource cap makes them useful without any major changes.
If harvester buff resulted in Economic station become no more useful, let agree that harversters's buff was too strong and they are needed to be adjusted apropriate way.