Jake you have to give a reason why it is broken. A really good reason. You can't just say "its broken because it is broken". What is "the idea of being broken"? You are just calling it broken without giving an explanation or insight on how the metagame would be better without it. Also you can't compare a broken pokemon (excadrill) to a possibly broken move (SR).
There are only 2 viable ghost in OU... Jellicent and gengar... With team preview you can easily manage SR as both of these pokemon are not super common anymore. If you get pursuit trapped then that is your problem as well. If you really want SR to be gone there are many ways to do it. Spinners are usually very effective if you play them right.
You can easily manage SR if your SR-weak mon is a one switch-in late-game cleaner and you dedicate your spinner to the goal of its late-game sweep. You can't manage SR to where you can use something as a mid-game pivot that HAS to come out a lot. Such as specs chandy or banded kyurem-b. They have the perfect resistances and stats to be high-ou with these sets, but they aren't and those aren't even their best sets in this meta. If spinning/magic bounce was so effective, than these sets would be effective. Defensive mons such as the 3 kanto bird and gyarados suffer even further since they usually make up part of the defensive core. You can't wait until you get a chance to spin to switch them in since they have to counter things and you can't switch them in because they will get owned by SR. If spinning were an effective counter, then you obviously not have to worry about rocks if you carried a spinner.
Powerful and no effective counters=broken. Almost everything that has been banned actually had counters(maybe not OU-viable ones, but yea), hasn't been this centralizing, and was not so efficient of a threat(efficient, not deadly).