I dunno... having multiple seperating 'branches' for various approaches you can take sounds fun. Want to be an uber-magical kingdom? Sure! Want to have the best economy around? Sure! Want to have the best military forces on the globe? Sure! Want all three? Nuh-uh, gotta pick one.
I always liked Civilization's approach to this. You can move ahead along a particular branch of the tech tree for a while, conferring a temporary advantage in that area, but, eventually, the increasing research costs and interrelated prerequisites catch up with you and you have to restore some technological balance to your Civ before you can progress further.
So you can choose what to be the best at but it isn't a permanent decision. For example, you can beeline in such a way as to have the first/best medieval army in the game but, assuming equal competition, you and your enemies are still likely to enter the industrial age at the same time, so that exploiting your advantages becomes a very immediate concern and so that a good start doesn't turn the remaining 80% of the game into a long mop-up operation as you exploit your continuous advantage in one area.
- Ash