I am using both and I have no problems with feeding and extracting at all.
This has mostly to do with the construction of the gun and can in most cases be fixed by a skilled gun smith if needed.
And the 375 Ruger doesn't give more pressure when making it go faster than the 375 H&H, because as with all thick and short cases, they burn the powder in more efficient ways than their longer and thinner brothers and sisters. Giving in fact lower pressure with less powder used to give the same speed.
How hot does it need to be to make a case a little sticky when hot?
I have never experienced this happening myself.
I have not been hunting when it has been very hot(more than 35 centigrades), but I have been shooting at shooting ranges at 35+ centigrades firing lots of shots, making the barrels almost glowing of heat with different cartridges and still not experienced sticky cases.
I don't always think newer is better at all
But I do really find it funny that some people can't accept that sometimes there comes something newer that is better. And cling to their old favorite and refuse to admit that the newer one is a bit better.
Nothing wrong in loving an old timer at all. I do that as well with many cartridges, but I still think that a few times there comes something that is better than my old love, but that doesn't mean that I jump ship and run for the new one when the oldy do the job plenty good enough for my use