3.5 DR is essentially the house rule I've been using since 1985 or so (I've never had an "adamantine" category and mithril works as silver). In the intervening ~20 years, I've never once seen "golf bag syndrome". IME, it's a boogeyman constructed as a knee-jerk reaction by people scared of a little change. Oh, and prior to 3E, DR was absolute -- in my system, a +400 vorpal holy avenger would do no damage to a werewolf unless it was silver. If golf-bagging doesn't happen in conditions like that, it ain't an issue.
I think the 3.5 DR is great. As others have said, the standard 3.0 DR rules made anything besides "ahrrrr, more power" a pointless stance. 3.5 DR actually has some personality to it and makes the characters deal with monsters in a more dynamic way (rather than just scaling up existing tactics). I do not see any way in which 3.5 DR is not superior to any previous DR system in D&D.