How to improve SRS and plus minus individual numbers

[Odinn21]

This will not be about providing a solution. I have some questions about SRS based on some observations. I’d like to have a conversation about this.

Like any other stat, SRS should be a subject of pace and three pointers study, right?

A quick example;
The Spurs in 2004-05 season; 7888-7248 total scoreboard, 7.80 MOV and 7.84 SRS, they outscored their opponents by 8.83% and had a NRtg of +8.3.
The Spurs in 2013-14 season; 8639-8006 total scoreboard, 7.72 MOV and 8.00 SRS, they outscored their opponents by 7.91% and had a NRtg of +8.1.

And while SRS adjusts for competition strength, the Spurs had 15th highest SOS in both seasons.

When we look at SRS without thinking further, 2014 Spurs look like they performed better than the 2005 version. But it’s hard to agree with that. The 2005 version outscored their opponents more by nearly 1%.
Surprisingly expected W-L numbers agree with my conclusion though. They favour the 2005 version with 63 to 61.

When we go to, say the ‘80s, it gets even more interesting because pace was higher but utilisation of 3 pointers was nearly nonexistent.

Then when we go even further back, to the early ‘70s, we have 1971-72 season which had 2 teams with 10+ SRS because the number of teams in the league was not high and they beat the weak teams senselessly and repeatedly. For example the Bucks outscored the Royals by 118 in 5 games.

Also, individual plus minus metrics as RAPM, do they consider percentages, pace and utilisation of three pointers?

What do you think of these? Do you know any studies regarding these?