I agree with most of your critizism, and there are some mods that fixes some of them.
There's the ECOMOD made by guineapig that adds a banking system along with some other cool new features like a stock exchange and the ability to own buildings in some towns.
I'm not sure it's compatible with BSM, but here's the linky anyways:
http://guineapig.byethost13.com/dl.html
There's also a small addon to the Blue Sun mod that adds 4 random encounter maps from 7.62 Reloaded. You need to have that game if you wanna use it, but there's a Ukranian web shop that accepts orders from Europe.
Here's the link to the addon:
http://rapidshare.com/files/38761794...Maps_Addon.rar
As for the BE5 maps I'm not sure it's possible. The random maps might be possible, but the city maps have some things, like locked doors and such, that might cause issues. But it might be worth while checking it out, I think more people have access to BE5 than Reloaded and the more variation in tactical maps the better IMHO.
I think the reason the devs made roof access so limited is that placing 2 mercs on a roof makes it too easy. When Istarted playing this game more than 2 years ago I used this tactic, but it makes the game boring pretty quick and I don't mind a bit of a challenge
