yep agree with your first point, I dont with the last 2. If you are going to implant a stock exchange etc, it will distract you from the core busines, transporting goods. You are now talking more like a Railroad Tycoon game, thats okey with me, but I think there are enough games like that. There is only one railroad transport game atm ttd. All others dont have the signalling/track laying capabiletys needed for a true trantsport game.
to come back to your first idea I did mean the same, the citys should produce a bit more pasengers, it is totaly useless if there is only one pasenger for every destination per month

Btw the destination could be related to the city sizes, so a large city has more ariving pasengers as the smaller ones.
one more point, If the pasengers only go to citys, you could say that if a station covers the centre of a town the town gets conected (the way transport giant probably will do it) for accepting pasengers. For the producing of pasengers the houses that are in the cover area of a station will produce them and maybe a choice if pasengers of 1 house will only produce for 1 destination, or will they produce a random destination? The 2nd will be harder to transport, every week the pasengers can go to a diferend destination, wich will make it realy hard making a good transport network.