Although nocho has provided us with some hard imaginary numbers, I think it is my duty to muddy the waters until things become clear (yes). Now, I haven't calculated values for ALL of our cities because I'm a little lazy, but I currently believe that a switch to Nationhood right now will net us less Espionage Points than under Bureaucracy. Here's what I've found.
By my calculations, a switch will result in these changes in Cologne: 35 units of Commerce, down from 53; 121.5 Espionage Points down from 156.6. So an 18-point drop in Commerce, and a 35-point drop in EP. I did, of course, factor in the 25% bonus from Nationhood into this final figure. Will the other towns make up for this? I estimated the new EP values for the four highest cities, other than the capital, and together they would get an increase of 25 EP, much lower than the 35 lost from Cologne, never mind the drop in commerce. We're already losing money at 60% EP. Whether things would even out at lower slider values, I haven't checked.
Based on these preliminary findings, I think that we would need to run a much larger number of Spy specialists to make use of Nationalism, as it would essentially increase EP from a Spy from 4 to 5 points. Of course, our ability to do this at the moment is limited by the fact that we can only currently construct Courthouses, which only provide a single Specialist Slot. However, I believe that future innovations in espionage and information-control will yield facilities that can employ additional spies.
I therefore suggest that we consider a cost-benefit analysis of whether it would be more beneficial to develop our new acquisitions towards hard commerce or the ability to feed more dedicated spies. Unless we come across some new financial windfall that allows us to run the EP slider at 100%, we should assume that for every point of Commerce that a city produces, at least 50% will go to the treasury. A non-riverside Town produces 4 units of Commerce. Two produce 8 and I use two because it would take about 2 farms to feed a Spy Specialist. 8 Commerce becomes roughly 4 EP before modifiers and 1 Spy produces 4 EP. Though if farms could be made, riverside Towns could be grown . . . . so a net of 5 EP from two Towns. Hmm, a dilemma.
It may be that locations that already provide a food surplus, such as from a food resource, may be best developed towards feeding spies, while those with less food may build commerce. This may result in a case-by-case analysis. I will conduct a study of our recently acquired lands to try and gauge the most efficient course, noting that it takes a great deal of time for a Cottage to mature into a Town, while food surpluses could be obtained much more quickly.
In conclusion, the only thing that I can say with certainty is that our net EPs are likely to decrease with a Civic switch, if only because the slider will have to be lowered.
Edit: The duration of my report has allowed Norvin to make a conclusion before me. I will conduct a new, more thorough study of a Civic switch at our current state and post the results.
The Revised Whosit Report
Let's just start with the numbers. As you can plainly see, I was far too hasty in my initial assessment than was Norvin.
Deficit: -71 gpt.
EP (60%): 496 eppt.
Cologne: Commerce: 53 > 35; EP: 156.6 > 121.5. (-18 gpt/-35 eppt)
Frankfurt: 20.25 > 24.3. (+4 eppt)
Essen: 57.15 > 63.5. (+6 eppt)
Dortmund: 11.6 > 14.5 (+3 eppt)
Ligurian: 9.00 > 11.25 (+2 eppt)
Stuttgart: 8.00 > 10 (+2 eppt)
Cuman: 14.00 > 17.5 (+3 eppt)
Uppsala: 12.80 > 16 (+4 eppt)
Nidaros: 16.75 > 20.1 (+3 eppt)
Birka: 5.60 > 7 eppt (+2 eppt)
Jelling: 11.6 > 14.5 (+3 eppt)
Haithabu: 14.00 > 17.5 (+4 eppt)
Bjorgvin: 25.75 > 30.9 (+5 eppt)
Borsippa: 9.20 > 11.5 (+2 eppt)
Sippar: 7.4 > 9.25 (+2 eppt)
Akkad: 14.6 > 18.25 (+4 eppt)
Dusseldorf: 3.6 > 4.5 (+1 eppt)
Babylon: 7.2 > 9 (+2 eppt)
Dur-Kurigalzu: ?
Berlin: 30.75 > 36.9 (+5 eppt)
Hamburg: 12.20 > 15.25 (+3 eppt)
Munich: 48 > 57.6 (+9 eppt)
New Deficit: -89 gpt
Net EP change: +34
Estimates of EP changes are approximate and don't fully calculate decimals, but it should be close enough for our purposes. Note that these values are for 60% EP slider. I would venture to guess that even if we lower the slider so that we are not losing quite as much money, at least not too far, that we will still have a net increase, though how much, I don't feel like calculating again.
Note also that a few Groceries are close to being completed, and we can still build more Castles that will increase both income (trade route) and provide a percentage bonus to EP. I suggest building more Castles as time and resources allow, though perhaps only in relatively high-EP cities due to the fact that Castles will eventually become obsolete.
Also, in the next 9 turns, several Grocers/Marketplaces will be constructed, which should negate the -18 loss from switching out of Bureaucracy, but will not otherwise pull us out of the current deficit.
On a completely separate note, we had best whip a lot of culture into our eastern Viking cities to stave off Gandhi's culture until we deal with him in a more permanent fashion. I will try to work on my Food vs. Commerce as Espionage Points thesis in the meantime.