To be honest, I wouldn't mind DC exploring this relationship one bit.
If you think about it clearly and without too much bias there's really a lot to work with here.
The fact that they are opposites on most things will only make it even more enticing for the open-minded reader.
(I hate pairing wars.They're the vilest, inhumane things and bring out people's true colors)
The verbal debates and clashing of philosophies as well as their different culture or customs could lead up to a really nice storyline for them to find some common ground.
Diana comes from an island of women and left it for Man's World to learn more about us while given the title of "Ambassador of Peace" to represent her own people.
What better person to show her humanity in all it's good and bad traits than a guy who knows the High Class Lifestyle of the Rich as well as the Low Class Urban Struggling of the Poor than a person who has lived it and seen it both as Bruce Wayne and Batman.
They are both warriors in every sense of the word and admire and/or respect each others tenacity and fight prowess to keep going when things look bleak.
Bruce has always been a guy who has trust issues, but when you give him a person who is all about trust (Lasso of Truth doesn't count) then it would freak him out because his excuses wouldn't work on her.
He convinced himself to believe that long term relationships wouldn't work; this just throws a cog in the wheel since trust and concern for his woman's/families well-being is at stake.
He doesn't have to worry about that if it's Diana. He's just afraid of seeing a ray of light called happiness in his dark bleak world.
I won't focus too much on the obvious "Light and Darkness" symbolism, but I sure hope one day the DC writers would give this pairing as much attention as others and really try to explore the possibilities here.
I'm always open to seeing fresh and new ideas and this counts as one of them.
The fragility of one person compared to the invulnerability of the other would be a great storyline all to itself. This may not be original, but there could be a moment of realization of his humanity that can ooze character development so much that it could take this union into surprisingly new unknown territory that we have yet to see in DC Comics.
I'm confident this won't reach them, but I'm hoping they would be fearless enough to do it.