Not so - it resamples to some very odd dpi figures if you try - very aggravating when backward progress is built in like this - I'm not the only one who wants the old "aspect ratio crop" then - Adobe are you listening ?
I actually find myself cropping in Photoshop less, doing it in Lightroom. But there are still occasions where I might need to crop in Photoshop.
If the Resolution box is empty, it doesn't resample, it assigns those dimensions to the image, then makes a corresponding adjustment to the DPI. This is the same thing as using image size with the resample box turned off. You can also indicate a final resolution, and leave the width and Height box empty, you will then get the DPI you have specified and the corresponding calculated height and width.
Only if you provide all three numbers will Photoshop actually re-sample the image to the specified numbers.
I agree, it would be nice to simply indicate a proportion in the crop tool box, much like Lightroom. But you can use the tool to crop to do aspect ratio cropping without the image being re-sampled, and then if necessary modify the image size settings without resampling to achieve a more appropriate range.
I personally prefer the crop tool because it is easier to modify to achieve your final crop. I normally put what I think my target final size is for the image. Often I only put one number in ... the longest side. This will then calculate all other numbers, and provides me a useful DPI number ... if the number is too low I either don't print that large, or occasionally will try a 200% uprez. I have been very pleased with the concept taught by Jeff Schewe regarding not interpolating to output size, but letting the printer driver handle it as long as the DPI falls within an acceptable range.