I know there will be a lot of new companies to make the stock market more realistic, and other things that will inject, and that is AWESOME! However I was happy you messed with it... But not as happy what you did... The number of cities. I don't think 7 is enough personally.
More Cities is the way to go. Choose the number for a game, possibly choose what specific cities you want in a game. If it's been discussed a lot sorry for the rambling below, but I think this would be the single best thing to do after adding more companies, and some of the other great things you already have listed on the new site.
I think this can add a lot of fun to the game in multiple ways. I for one like to run through creating new games until a set of "cool" cities pops up. It's fun to base your company out of a city like Berlin or LA or somewhere specific that you like. Even if still random something "cool" is more likely to show up each random spin with more cities.
I would say make the number practically unlimited, or whatever the max your back end can take is. Modern computers don't have much trouble running a TON of simple calculations like all the database stuff going on in the background of this game, so I wouldn't think there would be too much trouble with it choking a system. If there is at say "fast" game speed, put a warning that if you have that issue lower the game speed! I have a super fast computer and don't think it would bother my system at all.
Why you ask? Because it will make it more realistic. Having 7 cities is a big step up from 4, but it still doesn't give you the feeling of being in the real world. Now 20 cities would go a looong way towards that. You'd have multiple on every continent. 30 or something would be amazing. You could get really in depth in a super long drawn out game trying to hit a net worth of 500 Billion or something
It would also open up the strategy in several ways. For instance with some semi products, one plant can supply practically the whole world. With more cities that couldn't be the case, and setting up "regional" supply chains would be a necessity... And fun!
Also, it would allow specializing. In order to reach any real level of success you have to make a bajillion products as is. This is somewhat contrary to the real world. Most all companies, at least in the beginning (and often for decades), concentrate on one narrow field. More cities would allow you to become a billionaire leather magnate or electronics titan. This is more real, and pretty cool.
Also one could choose to be more of a regional powerhouse, and still be big. Maybe you make electronics, computers, leather, etc... All in Europe, because there are 7 cities just there. You could become a billionaire that way, while other companies are concentrating on the US, or Asia, or South America.
This would then lead into another "the plot thickens" situation. If you wanted to become the world leather master, it would take years. As it stands now you can setup in all cities pretty quick and dominate a given industry, even with 7 that will more or less be the case. If there were 2 dozen cities, it would take years to save up/borrow the capital required to truly dominate. In the meantime, maybe some company in Australia is doing the same thing... When 2 powerhouses in an industry meet, it could get hairy! You'd have to fight a strong competitor to beat them out of a market.
More cities would also allow a lot more room for new companies to emerge. The fact that it would be harder to globally dominate means more niches would be left open. Maybe North America, Europe, and Asia have their leather needs met, but South America has a few cities where there's no one doing it. Makes it easier for new competitors to get strong, hence be able to fend you off better, hence more fun when you crush them!
I have some other things I'd like to ramble about, but will save those for later in this thread, or another post. They're largely questions about exactly HOW you're going about working some of the features I saw on the site, or what exactly they do. All I ask is that you consider the above, and if you have to limit at 7 at least let me know why!