in the question about dogs i hot weather being insulated, has anyone ever touched a camel in person? they are desert dwelling animals who LOOK short coated, but upin touching them they have a very dense coat, the hair is light but coarse with an undercoat, this keeps them insulated from the heat during the day and extreem cold at night... same deal with a double coated breed.
if you let the coat accumumulate dead hair then yes it will not insulate properly, but if kept in peak condition, reularly brushed out and healthy, the cat will infact help keep the dogs core temperater MORE stable during temperature flutuations.
the analogy given is 100% correct.
a well kept coat of any lenght would be like wearing a cotton, it provides some protetching form the elements while still breathing, let it matt and accumulate dead hairand its insulating properties "malfunction" as it doesnt "breath" like it should, shave it down its like someone running round naked with no sunscreen on whos not used to the sun (ie someone like me, youll BURN)
Again this isnt even touching the hair regrowth issue which i dont knwo nearly enough to comment on...
i have seen sheps and chows shaved down and YES they look happier, but in all honestly the ones that have been shaved down and now look happier are also ones that didnt have neer enough proper coat upkeep, drastic shedding with no brushing and matts, so yes these dogs are going to feel better shaved becuase their coat was not taken care of properly.
in the case of matts, its not a matter of go ahead its ok then cause it wont effect it. its a matter of shaving and potentially damaging the coat is MUCH safer in many cases than trying to hand pick the tangles out, and while not the ideal course of action in terms of overall coat afterwards, its better for the dog in terms of being healthy, safe and comfortable, matts are painfull!
in terms of single coated pet breeds, i honestly think most look much better when their natural coat is kept in top condition and trimmed to how it should be, but most people arnt willing to put in that kind of coat upkeep on their dogs...