The 1993 Knicks had a Def Rtg of 99.7, 1st in the NBA, 8.3 pts/100 better than league average
For perspective, that's only slightly worse than the 2008 Celtics (98.9 Def Rtg; 8.6 pts/100 better than league average).
I think this kind of single-metric comparison gets tricky very quickly though - not only are you doing it across eras*, but, for example the Knicks have a net rating of 7.44 (because of their middling offense), a far cry from the Celtics' 11.38.
*If two teams give up 95 points per 100 possessions, which is better—Team A, which did so during a year in which offenses thrived, or Team B, which did so when scoring was down? Standard deviations away from the average do some work to explain this, but it also doesn't take into account rule changes and/or strength of competition - which you'd want to use DRtg/A for, usually. (This still favours the Knicks, so I'm not trying to disagree with your point per se).
I'm not arguing that the Knicks are better than the Celtics, though. I'm saying that their defense, relative to league average, was about as good as the Celtics. The 2008 team obviously was much better overall.
If somebody is convinced by the "the '93 Knicks weren't that good because they had Oakley and Starks as their second and third best players" argument, they may want to account for that team's excellent defense. That's probably more instructive regarding the quality of that team and why they won 60 games in their era, as opposed to comparing points and rebounds put up by Oakley and Starks.
They obviously were a great defensive team overall, but they played in an incredibly weak offensive era, which helps that. They really have no elite defenders on the roster. A lot of good solid defenders, but no DPOY candidates and very few guys even making the All Defense squad. The fact that they were consistently one of the best defensive teams in the league, sort of supports the point I was making i.e. the era blew so badly that a team like the Knicks could be that good.
You're underrating Ewing on defense. He only made a handful of All-Defense teams, but that's because he was in the same league as Hakeem, Robinson, and Dikembe. And, Oakley was 1st-team All-Defense in '94; Starks in '93. Anthony Mason was really good on defense, eventually making All-D a couple of years later.
The 1990s were the ugliest basketball I think we've seen on a league-wide basis, but some of the individual teams knew how to play together quite well. It's more of an argument for the Historic Draft threads, but I think that any team based around Prime Barkley, Prime Stockton/Malone, or Prime Payton/Kemp would be competitive in our era, assuming that those teams were constructed to take advantage of today's rules.
I will in particular love the 1993 Suns until my dying day.
Suns were ok, but Richard Dumas and Mark West were in the starting lineup which does diminish them. Dumas was a 2nd round 2nd year player, but was basically a rookie that year because he missed his entire 1st year on a suspension. Was suspended his entire 3rd year as well and played just 102 games in his career. West was on the downswing of an incredibly mediocre career. Bench was a good mix of vets like Ainge and Chambers and young guys like Oliver Miller and Ceballos, but neither of them was very good that year. Barkley was in his prime though and was excellent, KJ was a good compliment to him as was Majerle. If you equated them talent wise to a team of today, they strike me as a worse version of the Harden/Paul Rockets squad that also had Capela, Gordon, Tucker, Ariza, Green, Anderson. Suns won 62 games that year and made the Finals, they at least had a top 5 player though as Barkley was clearly that during that season.
