Pretty sure I wouldn't touch the Iconian ones. Granted, the Merchant Emporium is a little weedy, but the Merchant Trade Complex? That's basically an economic capital per planet, if needed!
I've spent the evening working on the new Iconian tech tree, which features Technology Strategy techs. These are basically the same deal as the Technology Progression techs, but the Super Project list is different:
Technology Strategy I - Centre for Intellect Studies, +20 to Research ability and +4tp
Technology Strategy II - Precursor Weapons Lab, +20 to Weapons ability and +4tp
Technology Strategy III - Galactic Technology Centre, +150% research on planet and +22tp
There's also four new Iconian improvements:
Precursor Repository - upgrade for Precursor Library, +15% research on planet and +20tp (respectively, 5% and 8tp better)
Precursor Matrix - upgrade for Precursor Archive, +20% economic bonus on planet +10% influence bonus and +14tp (respectively, 10% better on economic bonus and 4tp better on research)
Enhanced Invention Matrix - 50% more output than a regular invention matrix, but costs 50% more to build and maintain, too.
Enhanced Discovery Sphere - see above.
However, they lose Research Centre and Research Academy technologies, along with the improvements those grant. The Iconians didn't have Advanced Computing in the first place.
I may have to dial some of these back a little, so that the Iconians don't go into a late-game economic meltdown.