Well, not entirely like that. As the OP was asking a question about killing undead, and his answer was its up to the DM to decide. Some DM's would want to increase the destinction between dead and undead or change the ways in which undead creatures are killed. That is a feasible thing that a DM might change, the damage of a Longsword less so. Although to be fair I might like to remove the one handed option for the Longsword as you can't wield one effectively in one hand. I don't do that when I DM, but it would be a reasonable change I could implement if I was running a more realistic game. But I get where you are coming from. Saying its up for the DM to decide it hardly a helpful answer, but it is certainly never wrong.