An easy argument can be made that the tires have rendered DRS obsolete. The performance differential between a car on fresh tires and one on worn tires is enough for overtaking without any further assistance. However, this has been the case for most races since DRS was introduced, and yet that argument still sometimes falls on deaf ears, which is fine; we all have our preferences.
But, today we had the first retirement (I think?) due to a malfunctioning DRS when Schumacher's wing, for whatever reason, would not close. Aside from the competitive implications of such a retirement, this was a potentially very serious safety risk, too. It goes without saying that predicable grip is vital in F1, especially on circuits like Gilles Villeneuve and Valencia, where the walls are awfully close to the track.
So, is it time to ditch DRS?