After watching this thread grow to 16 pages with great interest, I've decided to chime in with a few thoughts, in no particular order;
if you beef up one area, you are frequently just transferring the initial failure to an adjacent area
slippery airplanes can reach Vne in a heartbeat if you're inattentive, especially when you are coming out of something that can't reach Vne unless you point it at the center of the earth.
flutter margins aren't something to be trifled with, nor are they something to be improved upon unless you have a big brain plus the ground and flight test equipment to back up your proposed fix.
A few of the modifications that are being talked about here aren't something that we would do in the certified world without a ton of modeling and static test articles, followed up by flight testing with an emergency egress system, pilots with chutes, and sometimes spin chutes on the flight test plane.
Yeah, I get that with a big enough statistical sample, you can predict X number of events over time, and this statistic seems to say that if you overspeed an RV7 you can rip the rudder off before the rest of the tail comes apart.
This set of statistical data would also seem to indicate that the builder has a choice; he can either install a big rudder and have smaller flutter margins (maybe) or install a small rudder and have poorer spin recovery characteristics. Pick one-live within the constraints of your choice. It's obvious where Van stands on this because back in the day they ponied up free rudders for everybody.
I'm going to take the stance that there isn't anything inherently unsafe about a well proven design, and be thankful that it's been in service long enough to identify potential danger areas to stay away from. Is it as forgiving as a 172? In this particular area, probably not. But you know what, it's not as forgiving of being left out in the rain either. That doesn't make it a bad airplane, just different considerations.
I could look at any two airplanes and pick them apart as to which one is better and which one is worse. A lot of you guys are old enough to remember when the first Citation came out and the Lear guys started saying that it was so slow that it was going take bird strikes from the rear. It wasn't very long before the Citation guys started saying that a Citation was doing everything it could to keep you alive and a Lear was doing everything it could to kill you.
My point is that like most things in life, you have to weigh the pro's and cons, mitigate the cons while being confident that the cure isn't worse than the disease, then live with the result.
This is an interesting discussion for sure, but as for me, I'm going to accept that my airframe has some well documented areas that need to be respected, with different considerations that a Cessna (or whatever). I'm building the airframe to it's well proven design, with the big rudder that Van's recommends/supplies and will try to live within those constraints.
edit- I have one final thought here; I've seen some comments about modifying stuff and the rebuttal has been "you're going into test pilot mode" followed by somebody else chiming in; "you're in test pilot mode when you're in phase 1" or something to that effect, implying that these two things are somehow equivalent.
I'll respectfully opine that no, in phase 1 you're in CONFORMITY pilot mode. You're confirming that your particular airplane behaves the way everybody is expecting it to, because that's the way it was originally designed and built to behave. If it's out of conformity with the rest of the fleet, then you try to figure out why and fix it, but it's extremely unlikely if you build to plan that something is going the be catastrophically out of whack.
In this case, it would seem to hold true whether you use the small rudder or big one you're in safe, well documented territory. They are both known quantities with known characteristics. But, If you go off the reservation with extra stiffeners or balance weights or otherwise start monkeying around with your own "improvements" without knowing what you're doing, you're truly in test pilot mode, which isn't where most of us want to be without significant training and safeguards in place.