STW2 has definitely potential to become my preferred TW, but so far there are too many items that might ruin it:
- Economy: the food effect on growth vs. market chain is really bad design
- Bugs: CTD is not that uncommon in my single player campaign
- AI: AI attacks my forts with equal stacks and gets totally annihilated
- AI: suicidal generals

If you fix the above, STW2 will become my favorite for sure.
Some tweaking of unit stats might be also good, but I have a feeling it will happen either through CA or mods for sure.

MTW1 and 2 are my favourites really. If you made a MTW3 with STW2 style skill/tech I would really love it. Copy the RPG elements added to the generals and agents and the game gets a lot better. Also, I like the fact that agents might contribute to the economy (like Metsuke) and that food supply is relevant (since it makes for different priorities of conquering areas).