Likewise, I have a model J3 as a matter of fact!
I still disagree with you though. If the IFR aircraft gives a concise call initially, rather than using IFR terminology, it saves Mr. VFR from having to speak up (which is hard enough for some people) ask where the hell "Whiskey Echo" is and it saves the IFR aircraft from replying, when they are possibly busy with their approach.
The initial call doesn't have to be long either! Like I said before all it takes is "approximately 15nm to the west, passing 4500' tracking for a 10 mile final runway 06" There is no need to mention the RNAV at all, for if it's CAVOK the J* is probably just using it for track guidance and not actually shooting the approach.
Unfortunately you can't assume that all the traffic in the area would be as scrupulous as yourself and had checked the approaches for that aerodrome!