If we're going for fantasy calendars, here's mine
Round 1 - Australian Grand Prix - Albert Park
Round 2 - Abu Dhabi GP - Yas Marina
Round 3 - Portugese GP - Portimao
Round 4 - Spanish GP - Jerez de la Frontera
Round 5 - Monaco GP - Monte Carlo Street Circuit
Round 6 - Rome GP - Rome Street Circuit
Round 7 - Canadian GP - Ile De Notre Dame
Round 8 - French GP - Paul Ricard HTTT (with temporary stands)
Round 9 - British GP - Silverstone
Round 10 - German GP - Nurburgring
Round 11 - Finnish GP - Helsinki Street Circuit
Round 12 - Belgian GP - Spa Francorchamps
Round 13 - Italian GP - Monza
Round 14 - Singaporean GP - Singapore Street Circuit
Round 15 - Japanese GP - Suzuka
Round 16 - Brazilian GP - Interlagos
Round 17 - United States GP - Caeser's Palace
My criteria are, in no particular order - classic circuits, distinctive ones, good excitement racing and going to places where there will be great attendances.
Like ESP posted, some related rule things
Pre-season testing limited to four pre-season three day tests at Barcelona, Valencia Ricardo Tormo, Vallelunga and Motorland Aragon. Two cars per team at the final two of the tests, one at the first two.
Post-season testing limited to one three-day test at Silverstone. One car per team at the first two.
Each team must nominate three drivers at the start of the season, each having to complete 250km at three of the four tests, running a continuous 50km within 107% of the fastest continuous 50km.
Seven European events being supported by the World Formula Two Championship : European Conference.
Australia, Singapore, Japan being supported by the World Formula Two Championship : Pacific Conference plus standalones in Korea, Indonesia, China and another in Japan.
Brazil and USA supported by the World Formula Two Championship Grand Finals, plus a standalone at Auto Club Speedway road course.
The reason for seventeen races, not more, is to accommodate other events in the motor racing calendar, including an annual World Cup for national teams (a little like A1GP, but without it's catalogue of mistakes) using either F3 cars or something like SCCA Formula 1000 with carbon tubs. My proposed venues are either a street/disused airport circuit in Nassau, The Bahamas or a circuit on the old airport in Athens, Greece. This would feature eighteen three-car national teams, with the tournament divided up in to three Pool Stage groups of six, two semi-final groups, a final group and a relegation round for the bottom two in each pool group, the bottom three of that being relegated to the second tier.