I somewhat like DRS, but as already outlined numerous times, its implementation is serioues flawed - either placed where it was already possible to overtake (Spa, Monza already mentioned), or in a position where the overtaker subsequently can be overtaken during the next straight (ie Malaysia).
How I would deal with DRS:
- a driver can use DRS at any time during the race when over a second behind the car a position ahead. This allows cars to be closer to each other (if they want!) and not have huge gaps half way through a race.
- when under a second behind (or if leading), drivers have limited use of DRS (ie can be used X times, or X seconds, during a race). This allows the leader to defend when attacked or to extend their lead at an appropriate part of the race (before pit stops, on fresh tyres, or if key opponent is stuck behind another car). It also allows following cars to attempt an overtake at any point they see fit!
For those that dont want overtakes done via DRS, maybe allow drivers to increase their fuel rate (for X seconds over a race) when within a certain distance behind car ahead (or to defend) instead.