I know that it hasn't been consumated and all of that, but how important could this marriage be in the long term if both live through the end???

I'm thinking this could be a power couple, if Sansa can stop being so dull and so manipulated by everyone.

I think Sansa's character still has some way to go - she's definitely learnt a lot in her time at King's Landing and the Eyrie. Right now she's definitely still dominated by Littlefinger, but honestly, who'd really be that surprised if somebody decided to cut Littlefinger's throat, just on grounds of being too slippery for words.

So who knows where she could be in a couple of books time? How significant the marriage will be is another thing tho- Tyrion's now over in Essos, and characters plans of action in return don't tend to fare too well round there.

Spoilerish

I really do think that Aegon and Sansa will end up being the queen and king of the entire realm i think GRRM will have spent 6 books destroying Sansas idea of a good man and i think Aegon will be exactly what she always wanted expected men to be

I think Arya will kill Sansa..

Then again I actually think nobody currently a POV character will survive 'til the end of the books. Many may survive to book 7, but when the dust settles, the Others will be defeated, and the peasants will have to rebuild.

Or the Others win because everyone is too occupied with taking the Iron Throne.