I've never really had a problem with SF units or helo engineers etc blowing bridges if a player wants to use them that way.
In reality pretty much every bridge in both East and West Germany would of been downed by both sides air assets anyway. As the game engine doesn't allow this I'm happy for other unit types being able to blow bridges !!
Theres plenty of bridging assets on both sides anyway. I for one quite often avoid static road bridges and build my own "out of the way" as it were, just to keep the enemy guessing as to where I'm crossing. On several occassions my opponent has attacked what he thought was my crossing point only to find I had mobile bridges elsewhere !