Friendly Fire, a tinkermage nerf & more flexibility in skill trees sound great. The additional enemy mental effects sound aggravating, but I rarely play on anything past 'Normal' so take that with a grain of salt
If we have to keep the re-training thing, can there be a real, permanent cost associated with it? Maybe you only get 90% of your skill points back? Having the ability to infinitely rebuild your character has always felt cheap.