Ok...
There is a lot of talk about whether the bridge should be destroyable or not. Here are some thoughts:
Destroyable Bridge:
1) Could be destroyed by bombing from the air, but would require MUCH more damage than a hangar. Down time could be short.
OR
2) Could be destroyed by "engineers", who would attack the bridge the same way troops attack the map rooms. 10 are needed to reach the bridge intact.
I think (1) would work better than (2), given that we dont have engineers in the game (yet). I also dont see the need for adding a whole new troop type just to take out bridges, when even on a large map, there would only be a few of them.
Right now, a hangar requires 3000 lbs of bombs to take out. If you think about it in game terms, a bridge like we are talking about "should" require more than that to take down... since a hangar is really nothing more than a corrugated metal building. A HQ takes 38,000 lbs of bombs to take down. So if a bridge were somewhere in the middle... say, 20K lbs of ords to take out, it would take more than a single attack to take it out.
Is that realistic? No. But it does solve the problem of Porkins taking out the bridge just for S&G's. Regen time on the bridge would need to be fast too... so Ol' Porkins cant drop his load, bail, and make another run.
Now... even if bridges were made indestructible, they would still be an important element if added to the game. The fight isnt really about "blowing up" the bridge... its about CONTROLLING the bridge. The fight is going to be cenetered at capturing the "Bridge Towns" on either side. Air strikes will still be called in to flatten the town on the other side... LVT's could still be used to cross up or down river to avoid a heavily defended bridge... PT's could still be used to provide support to the ground units, and/or enhance AAA capabilities. And when all else fails... RUSH THE BRIDGE with GV's and troops and try to overwhelm the defenders. And the best part is, both sides are going to be trying to take the opposing map room at the same time to secure the bridge. Can you imagine the carnage? Oh the horror!!!

I think the real point of adding the bridges are going to be for the strategic value of gaining the ability to get ground units into enemy territory. Take a look at the pic below:

By making the spawn points from the bridge bases the only way to get ground units across a river and into enemy territory rapidly... the focus of taking the bridge towns becomes gaining the ability to USE those spawn points. In the pic above, the "green" team has taken B2 and B3... allowing them to now attack A20 and A21 with ground forces. If they did not have B3... there is no fast way to get ground forces to those bases.
Would I like to see engineers and destroyable bridges and useable roads that effect GV movement and the ability to cut off supplies? Yes.... BUT, I think that the nature of AH2 is such that if bridges were destroyable, they would become targets of opportunity, taken out by high level, precision bombers with no real danger to being shot down. And that just isnt how bridges were dealt with during the war.
If I had to choose between having bridges set up in this manner, or not having them at all... I would prefer to have them.