I have been playing TW since Shogun and absolutely love the series. The game has become multi faceted when dealing with battles, story lines and diplomacy options but has remained linear in terms of economic development and units selection.
Economic game play enhancement aside, it would be extremely useful and fun to design and create units in-game to accommodate specific battle tactics & financial capabilities (based on our tech progress / Instead of or in addition to unlocking new, predesigned unit types) It would enhance the battle experience as well as the game experience as well. Although I must say, The new Hero's look amazing.
I'm usually a big fan of a little more hands on economic development style RTS but TW wasn't designed to be as trade/supply focused as other RTS's.