I agree that more top players would be good for DC. But top players are self centered (understandably), so the reward in ranking points should be much higher, if the idea was to attract them...
The only thing I don´t like about the format is that it is still possible for a "one man team" to win a tie. It is hard, but a guy on roll can do that (I remember one time the Brazilian team beat Spain with Kuerten winning all his three matches). I would very much like changes which would force teams to use more players (during a single tie, not all year), so depth would prevail over a singular talent.