1: I think it's fine to scout around super far in my opinion. It doesn't add too much power into the game because you can usually see people on the horizon a good distance off just on yourself. Unless the imp also triggers ambushes, then there might be a problem.
2: A warlock's imp is able to attack normally in D&D 5e so that's no true shock. Enemies not attacking it back is a really weird though. That sounds more like a bug, or enemies are designed to just flat out ignore familiars and go for the summoners.
3: Making independent skill checks actually would be awesome for the warlock familiar and not the other classes familiars spells.
4: I'm actually surprised they don't have darkvision already on imps. They normally should have darkvision as powerful as a drow.
Last edited by Medirby; 08/10/20 11:25 PM. Reason: Edited 1 because the wording was off