In the original Monopoly game, the basic strategy is to control entire sets of properties. Even better, control contiguous sets of properties so that you increase the chances of a player landing on one of the properties you control. This fundamental concept is missing in MSC. Here are some ideas on how to provide something similar in a global street game.
First, rent must be based not only (if at all) on street length, but on how many other streets in the area or intersecting the street are owned by the same player. One way to do this would be to value streets based on the number of intersections they have, and then count intersecting streets owned by the player towards a rent multiplier. I made a post to this effect on the MCS blog and received encouraging feedback from other posters.
For example, by making each player owned intersecting street add some amount to a multiplier, you encourage players to own grids of streets so that you maximize the multiplier for a given number of streets. Owning 2 streets, the maximum rent multiplier is given by any two streets that intersect. But with owning four streets, the maximum rent would be obtained by finding two sets of two parallel streets that intersect, a grid type arrangement. This expands to any number of streets, always the most valuable arrangement is to control a grid of streets in a single area.
This system would strongly reward players who manage to control an area of space. It also naturally makes cities with many close by intersections more desirable than long empty roads in the wilderness. I'd be interested in any system that accomplished this goal, whether it resembles my intersection based model or not.
Another important aspect of the original game is that a particular street has a different value to each player. A street that is the final part of a set owned by player A is worth much more to them then it would be to player B who owns none of the set. A system where a single item can have different perceived values to different players is essential to a good trading system. The current MCS system gives every street the same value to every player, and leads to little competition or trading until valuable streets are exhausted. A good game would have trading as an important aspect at every level.
Well those are thoughts for now. Comments and better ideas are welcome.