Spring RTS Engine

Now that BAR seems to be close to complete, was there ever any design document or guidelines written for BA development?
For example, under what circumctances will a unit be removed from the unit roster? Are there any such circumstances?
What is the average game time per game BA is aiming for?
Since players obviously have a limited amount of attention and clicks per minute, what should be the focus of the gameplay experience compared to other RTS games?
Is it cycling through unit build queues, changing them all the time to tailor your unit assortment to counter your foe's? Is it unit movement and accurate individual unit placement?

In Spring's hayday BA's Unit balance leaned more towards certain individual units being "central". After some criticism and a call for "better" balance, dominating units like the flesh tank were nerfed in order to allow other units in the t1 tank lab to show their colors.
The downside was that on tank maps, like Comet Catcher for example, the focus of the game shifted more towards changing unit build queues in labs and making sure you are building the best unit type for the current map state.

So, now that BAR is almost done, isnt it time we analyse what BAR should really be about and how it's balance should or should not change in order to best exploit the spring engine and the existing map set?

As a BA player, I might say I'd like it to be a longer lasting game where every unit has a weakness, and micromanagement is key, map control is important and there is nothing 'op' yet nothing useless, each unit has its weakness yet nothing too weak. This means I prefer the t2 game, yet I strongly dislike games where everyone has a massive eco. Yet I also like larger, more complex maps, because there's more ways to attack the opponent, more weak points on the map,

I don't mind a unit (or unit group - aka ships on water) being 'op' in one area of the map, so long as it's not op on the whole map. Like a mountainous map with plains where veh might rule, but then you still need kbots to get over the hill. So long as kbots should be able to push back down.

I think changing unit buildlist is fine - I live for that kind of adaptation.

The one issue I do see in current BA is the effectiveness of defence. Currently, mainly in t1, it's useless to attack against most kinds of defences, because you have to put more into destroying them than it took to build them. Shellshockers/guardians are too expensive to invest in also because if you've built them, the enemy already has t2. Not that I mind it being a t2 game. But I dislike how t1 units seem completely useless sometimes. Maybe this is different in BAR already, but afaik BAR is quite similar to BA.