I'd have two suggestion/comments, mainly on the unit training and building system.
I) Unit training:
At the moment, your recruitment cost are representing both training and equipment costs. How about lowering the costs depending on:
a) Training level: Both by using men from the last year and forcing them to train during the whole year (i), a bigger cadre of trained men would be available, decreasing training costs and necessary training time. And, of course, increasing experience.
b) Equipment cost: Possibly by increasing the available weaponry, or by using weapons already existing (for example, Militias, or emergency Militias and of course equipment from former years.)
Combining these two would make it possible to, for example, stockpile swords and, in emergencies, recruit the veterans of last year in only a week or so, culminating in an experienced and well armed force. Of course, this would (maybe) make it necessary to track veterans a bit, so that an enemy army would target the now-civilians.
II) Away from the civ building system.
I for one am deeply, deeply annoyed by the civilization (or total war) building build system, mostly because you have to build things like a tavern yourself, which requires two or three years to build. Instead, I'd have two ideas:
a) Civilians build civilian buildings: Smaller buildings like inns, houses, shops and so on are built automatically (assuming of course that they even have an influence)
b) You can build as many buildings at once as you like - assuming you'd have enough resources, enough builders (both untrained and trained) and enough money to pay for those. And, you can vary those amounts.
Combining these two would result in, for example, a naturally growing city which, after some time, would've attracted enough builders that you could build a cathedral or so, or alternatively several guard stations or such simultaneously.
And, while typing, another idea crossed my mind: How about making a city not contain 'n people', but 'n people with profession x', depending on resources, buildings, and so on, combined with a immigration and emigration? For example, building a cathedral in a city would result in many builders immigrating to that city; a war in most people trying to emigrate, but several professions (blacksmiths, for example) immigrating. Depending on your chosen 'openness' for your cities.
Of course, only you can know how it fits in your concept and the time you're willing to invest.
(i) Edward III declared in 1363: "[...] that every man in the same country, if he be able-bodied, shall, upon holidays, make use, in his games, of bows and arrows... and so learn and practise archery.", see
http://en.wikipedia.org/wiki/English_longbow, under training.
Edit: Forum didn't like my citation style.