Personally, I see it as proof that I was right to say that secondary effects should go, or at least they shouldn't be able to influence the primary effects. It's just bad design that gives too much importance to the RNG.
Then there's the fact that there were apparently plenty of people who would risk getting their accounts banned just to go a couple of percentages beyond what should be the limit. Well, congratulations.
As for people reporting the exploit to FD earlier: let's not forget though that it's not like they can publicly acknowledge it before there's a fix, unless it becomes widely known through other players. Looking at the timeline of events, assuming that the screenshots are genuine, it was reported less than a month before the 2.3 beta. There should have been a fix there, but there wasn't. It probably wasn't a priority, because there were more serious things to fix, and as far as exploits go, as established above this one doesn't give a huge increase above what's possible through normal gameplay. In this regard, I'd say that the various money-making things that have been persistent (Ceos, Robigo, Quince, et cetera) were actually worse. The difference between them was that they were plainly evident and didn't require looking to break the game, or triggering them by rare accident.
If I were a designer for the game, I'd suggest rebalancing the blueprints to include what could before be gained through secondary effects, and then remove secondary effects from rolls, or at least exclude the ones that would modify the primary effects further. For example, raise the maximum possible optimal mass for G5 FSD mods to +58%, and introduce the max fuel per jump to the primary effects too. That way, there'd be no need to change existing mods on players' ships, and you'd get a more intuitive system that also relies somewhat less on RNG.
But hey, I'm not working for FD.
Oh, and goemon: if there's proof that somebody used the exploit, there should be no need to remove their modules because they'll get banned anyway.