London is not an aggressive opening. London is a solid opening with attacking resources. I personally don't like London, but doesn't matter. Queen's gambit declined is rather a positional opening than a tactical one. If Black plays solid, then it has huge drawing capabilities. Specifically in the Exchange variation there can be lots of tactics... But hey, I don't even understand what do you want.
londor or queen gambit declined exchange. what ??????????
Poryg is correct
London is not an aggressive opening. London is a solid opening with attacking resources. I personally don't like London, but doesn't matter. Queen's gambit declined is rather a positional opening than a tactical one. If Black plays solid, then it has huge drawing capabilities. Specifically in the Exchange variation there can be lots of tactics... But hey, I don't even understand what do you want.

The Queens Gambit Exchange can get quite tactical, e.g.
http://www.chessgames.com/perl/chessgame?gid=1074313
http://www.chessgames.com/perl/chessgame?gid=1771440
http://www.chessgames.com/perl/chessgame?gid=1584037

Yeah, the Exchange variation can be quite tactical. But Tarrasch defence is symmetrical, therefore quite drawish. Chigorin is antipositional and leads to some trouble for Black, although it is tenable and playable. Classical variation is just classical :) like in other old openings, even here are lots of resources, but the pawn structures are mostly symmetrical too. And Lasker defence is highly positional, because Black accepts an inferior position to defend. It's not that hard to defend, but still, seeking counterplay there is hard...
I have played both but london is an agresive opening. Queens gambit declined exchange is an tactically played opening.