@Vulpinenin Yeah, i agree about lower rewards and downgrading. Its not meant to compete with Nightmare, but to offer a "lower step" difficulty in addition to it.
Regarding counterspell - its RNG to roll it. However even if you do roll counterspell, unless you're always spell hit capped, there's a good chance your counterspell will get resisted, meaning instant death. Which means generally its much safer to just avoid them completely, and only use counterspell in emergencies.
Like i said before, im fine with casters being deadly for Nightmare mode (it is, after all, a nightmare). As long as there's a slightly less nightmarish option for future playthroughs, for people who already did the Nightmare once.