The fact is that fewer and fewer of the top players have played Davis Cup in the last 25-30 years. The reason most often cited is schedule and the need for rest, yet players continue to play exhibitions for money, so clearly this is not a complete answer. Furthermore, since Davis Cup has no bearing on points, a player is forced to choose between on the one hand:
- Earning a better living
- Saving themselves for tournaments that count towards ranking
- Playing Davis Cup.
For this reason I suggest counting Davis Cup results in the entry ranking system - just like they consider results in the "official" head to head records. It's not like taking points for something arbitrary - these are tennis matches played in earnest by professional players.
The intent is to ensure more participation in Davis Cup from top players, by eliminating the need to sacrifice tour points by playing Davis Cup. I would do so by awarding tour points for victories in a Davis Cup tie. The problem is that players not able to play Davis Cup cannot access those points, and thus would be at a disadvantage to those who can/do play Davis Cup.
To rectify that, I suggest ATP sanctioned tournaments scheduled on Davis Cup weekends, for players who cannot play in Davis Cup (either because they haven't been selected, or because their countries don't/aren't participating). Because in Davis Cup a player might lose one match and still earn points in another - not possible in single elimination tournament play - I suggest a round robin format giving players not playing Davis Cup the same opportunity to lose one match but still have a chance at tour points.
So in the end you have the following:
- Points awarded for victories in Davis Cup
- Additional points for winning a match in a Davis Cup tie away from home (mitigating the home court advantage)
- Points awarded in round robin competitions outside of Davis Cup
- These competitions are scheduled on Davis Cup weekends (no scheduling advantage)
- Any player (Davis Cup player, or not) can earn points on that weekend (no ATP points disadvantage)
- Players can skip those tournaments and rest, but sacrifice the points (just as they would any tournament they skip)