Re: I have a dream!?
We currently print to a custom press setup that tries to match a SWOP separation (as seen in Photoshop when not doing soft-proofing but using Adobe's default CMYK profile for U.S., U.S. Web Coated (SWOP) v2) for all customers but one, and am in no hurry to implement GRACoL2006_Coated1v2 for our other customers because they haven't complained and our printing is close to GRACoL2006_Coated1v2 anyways.
GRACoL2006_Coated1 is characterization data IDEAlliance released and is based on the new G7 method of setting up a press. This G7 method tries to aim for defined visual densities and/or L* values throughout the scale using defined CMY percentages and defined K percentages (hence the G in G7 means gray, and the NPDC's aka Neutral Print Density Curves for CMY and K. The 7 in G7 stands for the seven solids defined in Lab that need to be matched within tolerance: C,M,Y,K,CM,MY,CY. This differs to the international standard's implementation in Europe, which defines specific densities (but also like G7 says that Lab values are more important, so they actually aren't really different here) and specific TVI aims (where the two really do differ, because G7 says that gray balance is more important than TVI and the international standard says TVI is more important I think).
I made an Excel calculator that I used to fix my existing plate curves to match GRACoL2006_Coated1v2 and the pressmen are able to match the GRACoL2006_Coated1v2 proof on press. I tried to attach the Excel document (made on Mac Excel) but was not allowed to attach an .xls or .zip file (would like to know what I can attach then?!), so I can send it to you personally if you'd like. It will show the TVI differences between GRACoL2006_Coated1v2 and ISOcoatedv2 (both official IC profiles), and can also see how close the solids, overprints, and paper are between the two. I got the Lab numbers and did the calculations based on instructions and math found on Bruce Lindbloom's (color scientist) website (which I did another version based on Don Hutcheson's - current chair of GRACoL - math and both were in agreement with each other as far as TVI was concerned). The crux of the matter is that GRACoL2006_Coated1v2 is about 2-3% higher in TVI in the midtone in all separations than ISOcoated1v2. Enough of a difference to just tell a visual difference, but that's about it. With only this difference, it seems it would have been better to just adopt ISOcoated's NPDCs than make new ones that tried to match TR001 more (which matching TR001 makes old SWOP images look "natural" when printed on GRACoL2006_Coated1v2, but seems to have added confusion because we still don't have one universal characterization data/profile for each paper type where we could. If you have a press run with linear plates and you got to gray balance, use the NPDC chart on the 5th sheet in the Excel doc to get TVI changes needed. If you have an existing ICC profile of your press/paper/ink combo and have close paper and solids to the standard already, then you should be able to use the TVI calculator for individual TVI for each color (sheets 1-4 in Excel doc), use the 50 TVI change it recommends and average the 25 and 75 changes recommended to make them the same, change your plate TVI by that amount and smooth the curve, and you're good to go. I can't say it will definitely get you there, but my calculator has not only helped me, but also another person used it successfully to implement GRACoL2006_Coated1v2 at their site.
To get Lab values to put into the Excel calculator, download the official profile GRACoL2006_Coated1v2 and/or ISOcoatedv2 and in Photoshop's color settings, choose the official profile as the CMYK profile and set rendering intent to Absolute Colorimetric. in the Info palette, set Seconde Readout to Lab Color. Then (using the downloaded "LabDotGainCalculator2.tif" from brucelindbloom.com or self-made tint blocks in 5% increments for each color) take the Lab readings, which you'll plug into the Excel calculator.
BTW this can all be done faster and more precisely with IDEAlink Curve software from IDEAlliance, so I've given this as the free option because I did the research and built it and it's worked for me.
As to your question, let's say we had one universal ICC profile for each paper, or two profiles for each paper, depending on the specification used (GRACoL2006_Coated1v2 or ISOcoatedv2). We know when we make plates that each platesetter/plate combo may need it's own calibration curve to make the plate linear (50 in file = 50 on plate), and we also know we need a bump curve to make the press print to the specification chosen (GRACoL2006_Coated1v2 or ISOcoatedv2). So no matter what, if plating files for one press or multiple presses, you'll need a calibration curve to make the plates linear in addition to a bump curve for each separation to match the specification. No way around it. I may need to increase my 50 to 54 to get linear plates while another platesetter may only need to move 50 to 52 and another platesetter may not need a calibration curve. Also, after getting linear plates, one press may need a 5% bump to get to specification aim TVI on press and another may need more or less, so I just can't see ever getting around this. Believe me, I have wondered the same thing as you before, but this is what I saw when looking at the situation.
FYI, GRACoL2006_Coated1v2 we use for one customer who constantly approves the proof then likes to "paint" on press, and us using the latest PANTONE color bridge CMYK numbers and official GRACoL2006_Coated1v2 profile for our proof, and matching that proof on press, has not stopped them from painting on press.
Don