I thought Clarke should have held off the declaration a bit longer. While I thought the target was too generous I was more concerned about the shape of Harris, Siddle and Starc and whether they still had it in them to defend such a total. The almost result suggests they didn't.
As for the light rule, it's one of those that fans like when their team gets the benefit, but hate when it goes against them. Australia were on the bad need a few times in the series and it seems the rub of the green balanced out and it (plus a slow down by Australia) prevented a loss. No doubt if it was England 9 down with Andersen and Kerrigan in when play was called off the booing would be a lot smaller and likely drowned out by the cheering.
Anyway, in the end it doesn't matter. England won the Ashes handsomely. Australia looks like they might have figured out one or two or their problems, but the other half dozen are still floating around. Australia needs to hope they can deal with some of their issues and that England's batting line up doesn't suddenly click if they want to get a different result at home.