I think non-improv audiences are a lot smarter than they seem to be given credit. Edits, tags, multiple characters, any reasonable audience is going to understand these devices with a little suspension of disbelief and paying attention. If they are constantly asking the person next to them what's going on, they were probably doing the same thing when they watched Avatar.
I actually have found that non-improv audiences are more inviting than improv audiences. They just want to laugh and see something funny, and are rarely worried about what's "good improv." Funny is the end all be all for a non-improv audience. Look at Asssscat. Teachers are constantly saying not to watch Asssscat to learn good improv, but it's hilarious and the non-improv audiences regard it as the highest form of comedy.
Openings, I will agree, are not very approachable, not because they are confusing, but just because a lot of them are fucking weird. A team asks for a suggestion and then pretend that one guy is a balloon for 4 minutes before ever doing a scene. That's avant garde-y and annoying to non-improv audiences. It's supposed to be comedy, not weird performance art. But funny is funny, no matter how much improv training you have.
If you want to ask someone who has a lot of current experience with both, ask the Tourco members that perform on Harold night. I bet they know a few differences.