The problem with redefining marriage, is that once you allow for this or that group, then you open Pandora's Box for every weirdo group (e.g. multiple partners, marry your sheep, or dog or whatever!). Don't change the definition.
You want 'benefits' of getting married? Get married!
You want freedom from rules of marriage? Stay unmarried!
Want Inheritance? Get Married.
Don't like it? Stay single.
Know the rules and work them for what you want, just don't whine because society won't change for you.
Good point about the Pandora's box. I agree that's a tricky one.
I still however, do not think we ned an anti-gay marriage amendment.That's way too much government interference in our bedrooms. Leave it state to state. and lets see where all this goes.