Really good gen sir.<snip>
Certainly, there's going to be a lot of improvement possible at the architectural level of the game, especially considering how old the engine is. However, this is where business realities really do become the limiter.
If you review updates for PDS' various games, you'll see a lot more investment in trying to improve the performance of games at a higher level. This is 'cheaper', and has proven to be an effective way to get short-term improvements in performance on more easily quantifiable issues (as they are exposed and perceivable by the player, and to a greater degree, the modder).
This is also the level where myself and other modders can work.
Your analysis is informative, but I'm not sure it will really influence PDS' methodology for addressing performance concerns with a game.