« on: December 13, 2012, 11:51:52 PM »
Speed, speed, speed. Focusing, fps (though mirrorless are surpassing DSLR's here, putting aside focus tracking) write speed (due to CF cards over SDHC), shutter lag (and no EVF lag like on mirrorless); just faster everything meaning you have a higher chance of getting the shot.
IQ wise, the bigger individual pixels equate to better images all-round - better dynamic range, colour accuracy, low light, etc. It's not just about megapixels when it comes to the bigger sensor in a DSLR.
RAW Files - yes, some upper range p & s cameras shoot RAW, but there's more to the puzzle than just that - DSLR's are designed to handle all that data even in burst mode, with faster write speeds and deeper buffers. Most p & s cameras with RAW capability mean you compromise on speed, which is critical in many situations.
Ergonomics - intuitive button layout that lets you operate the camera without a magnifying glass and tweezers. The extra size and weight can also help in stabilizing photos.
More control - yes, some p & s cameras and most mirrorless give you full manual control, but this goes hand in hand with ergonomics. DSLR's let you make changes instantly and blindly with ease, rather than digging through a maze of menus or trying to hit a tiny little button without also mashing every other button.
Lens choice - You say that this is a moot point because of mirrorless, but that's not entirely true. AF performance can suffer, sharpness can drop (due to pixel density & the crop factor which essentially magnifies any lens flaws), FOV changes and balance can be effected (which effects the ergonomics) when using DSLR lenses on a mirrorless camera.
Connectivity - need to operate the camera remotely through a PC? Or need multiple external flashguns? or you want to synchronize multiple cameras? DSLR's are your friend when it comes to these complex applications and workflows.
Additionally there are all the other little things that make the cameras "more professional" - dual card slots for redundancy, durability, battery life, custom filenames, copyright info in the exif data, etc etc. Of course any of these things can be built into just about any camera - but not without compromising the things that make those cameras attractive in the first place such as compactness and price.