If the battle log is easier to read and alot more customizeable than the current one, and lag wasn't terribad, then I wouldn't see the need for a DBM-like addon for myself. I'd LOVE one for right now, though. They could make it account for the lag, like some addons for WoW which would show you the part of your cast bar that is just lag so you can know exactly when you can start moving near the end of your cast and have it go off lol... But yeah, if that won't be an issue in ARR then there's no point.