I never said anything about needing water cooling for 2011 That is insane. I just maintain that it is ideal on larger die higher TDP chips due to the laws of thermal dynamics. As long as your cooling unit is able to handle the max heat spikes at load and the full load itself your good. Air cooling works well on 2011. And yes while you could put a NH-D15 on a stock 9590. I wouldn't, I own one and the Thermaltake water 3.0 ultimate (360mm rad) I have barely keeps it in check. To be fair it is overclocked some and the VRMs will overheat before that monster throttles down because of core temps, so that's a thing. Different problem. No 220 watt stock processors for noobs you will burn your house down!
For newer users and overclockers alike hear me! Water cooling is great, it's also expensive. AIOs are great they are relatively cheap, quiet, and effective. AIOs are not custom loops, you will not "max out a chip" on a AIO unless you have a dog with a really low voltage threshold. Therefore, high end air cooling ends up being very competitive with AIOs performance wise. On 1150, 1155, and FM2+ and basically any small die chipset this will hold true. On larger chipsets where it becomes a matter of the amount of heat rather then moving the heat away faster water cooling becomes more competitive when it comes to overclocking. While water cooling also transfers heat away faster it's a moot point, the real point is Air > AIO > H2O > Phase Change > LN2 > liquid helium.
No air cooler I am aware of made today competes at or above the level of a 280mm AIO, doesn't matter the chipset, doesn't matter what test. These 280mm AIOs can be had for around 110$ USD, a NH-D15 sells for around 90$ USD. is that 20$ worth the small increase in performance? Probably not, still some people (myself) would rather still have the bigger better thing. remember price for performance is king an AIO on sale is better then a V8 or a D15 at full price.