Well folks, a night of research has me feeling obligated to share my findings.
Drilling rotors was a fix for the brake pads of old. About 20 years ago it was common for brake pads to produce gasses above a certain temperature. A temperature they often exceeded from city, and most especially highway driving and racing. The use of drilled holes allowed the gasses to escape and would prevent a loss of braking by maintaining the contact between pad and rotor.
Slots scrape a layer off the pad which helps prevent glazing of the pad. Essentially the pad will gloss over if it gets too hot and the coefficient of friction will reduce to a degree that can cause sever loss of braking. This was a huge issue for semi trucks, hence the "run away" issue we used to hear about and the reason there are those hills for them to drive up along the side of the highways at the bottom of big hills. Don't miss a gear!
Anyways, this still serves a slight purpose of removing a layer of pad to maintain a clean and consistent surface. Which can be good for off road driving as it helps to maintain the pads surface after crushing it against the rotor with dirt or sand behind it. The slots help to keep things clean and consistent.
The truth is however that a quality set of pads these days does not produce gasses at the temperature range they are subject to. By the time the pads got to the temps required to produce gasses now it is most likely your brake fluid will boil and you are screwed.
Also, new pads are none too likely to glaze anymore either.
Today the benefit of cross drilled and or slotted rotors are for the most part pointless. They put them on sports cars because they look cool and people think they are sporty. They sell well for the same reason.
The negatives are that the holes are weak points and are prone to cracking. This however will be unlikely to be an issue for an every day driver and is mostly an issue seen on the track when the brakes are used extensively at high temperature. Race cars that still use these rotors typically replace them every race, sometimes even during the race.
The proponents for their use mainly state that a reduction in rotating mass without the loss of diameter is still a positive factor, and they don't care if they crack because they can easily be replaced along with tires in a pit stop.
Opinions, and the data supporting it, that debunks the advantages of drilled/slotted rotors is that a reduction of mass means a lower heat absorption capacity, the holes produce weak spots on the rotor and pads don't offgas anymore anyways, and basically the same argument against slots.
As for warping, did some good research into this as well. From what I have found the culprit is not warping of the rotor at all. It is in fact brake pad material that is unevenly coating the contact area on the rotor. How this happens is when we come to a long hard stop and then proceed to stand on the brake pedal, which causes the pad to basically melt to the rotor a bit and leave a nice print of itself behind after we let off the brakes and drive away. This leaves a spot on the rotors that has a different coefficient of friction than the rest of the rotor causing vibration as the rotors turn past that point. We do this all the time when stopping at a light at the end of an off ramp on the highway.
Apparently the best methods of combatting this are high quality pads that are less likely to "print" at these temperatures, which sounds like ceramics are good or something something carbon pads(sorry I forget exactly what they were called), also to let off the brakes after the stop if you can. Also to bed the pads really well after doing a brake job helps, having the rotors turned every time you put new pads on, especially if it is a different brand or material type of pad. Bedding new rotors or turned rotors is essential.
This is what I have found. It is from multiple sources ranging from racing forums, truck forums, brake manufactures, and the experience I found on a corvette forum given by an automotive engineer who spent his career designing brake parts and systems. The information is quite consistent so I am inclined to take it as it is.
Quality solid rotors and quality brake pads of the proper material for the type of use will give the best performance and longevity.
I hope this helps others who are looking for this information, and if anyone has any more to say about it I am interested to hear more opinions and especially interested in more hard data and testing info on the subject if anyone has it.
