No point in crying, as any relative normal poster said- so far this is the best DA could do. I think that after the flood of "how to sign LeBron" threads you don't need more explanations on how salary cup works.
Bottom line is- once you get a solid championship contender there is no room for major upgrades beside min vets and MLE. J o'neal was by far best option we had for using MLE, big man was not a desire, it was a must to sign as soon possible.
Yes, teams did get better, teams that were nowhere past season.
Miami is in the same theme as we are now for the next 4-6 years, Any future signing for them will be either MLE or vet min with exception of few trades which rarely get you big names (there are only few Gasols per decade you can get for free).
After serious threat that after heartbreaking loss we would end up "rebuilding" (read as= mediocre team) for next few years this is huge sucees.