Both removals make sense for the P&P, no Dm wants to calculate flat DR every turn on multiple attacls and immunity against magical weapons below +X is an incredibly annoying mechanic.
Yep. You are right. 5e is not the best edition to play but is the best to DM. Many "rental DM" asks more to DM 2e, Pathfinder 1e/D&D 3.5e than 5e by this reason.
When i played 3.5e literally nobody in a group of 8 wanted to DM and we ended making a "DM queue", where each one DM a session. We let the players calculate this stuff. However, most creatures with DR tends to have 5 or 10 DR, which is not that hard to calculate. For necromancers and people who wanna create army of undeads, we had a homebrew rule that they are threated as a group, and other homebrew rules to speed up the combat. IE : 20 skeletons attacking a single enemy when they have each 40% chance to hit means that 40%"of then will hit and everyone will deal the average damage. The player calculate it, not the DM. We also played a session where everything, from players and monsters are "maximized" ie - deal the maximum damage. The combat was pretty fast.
s in, it's almost non-existent. Having proficiency in a skill only gives you a 10% advantage over those without proficiency. At least at the start.
Not only that, a lv 1 ranger and a lv 20 has only a difference on 6 AB. Yep. Someone who learned how to use a longbow yesterday and someone who reached the peak human capabilities with a longbow has only +30% chance of hitting a enemy. In total, a fully maximized ranger is only 40% more likely to hit than a UNproficient peasant.