Spurs should have resigned Dedmon and Simmons (I was porbably the most vocal folk about not resigning Simmons in the offseason, but if you were going to commit all that money on Mills, Gasol and LA; you might as well resign Simmons, tbh), let Mills walk and not extend Gasol nor Aldridge, tbh.
Could have had a roster of:
Murray, Forbes, White/Tony
Green , Manu, Paul
Kawhi, Simmons, Anderson
Aldridge, Gay, Bertans
Gasol, Dedmon, Lauvergne
And all the cap space in the World in a season, or two, to try and get that one or two pieces that are missing to trully challenge GS.
Now we are stuck with a team that we know it's not good enough for, at least, the next three seasons. This isn't hindsight either (with the exception, in my case, of Simmons), this is what we were all asking for during the offseason (sans the pipe dreams of CP3 or Paul George).