fraglandsValve didn't intend "general applicability vs. special applicability" to happen in competitive, and that it was an unintended consequence of balancing for pubs.
wat. this doesn't make any sense (imo)
That's not how game design works. TF2 has a pretty consistent underlying philosophy of how each class functions and is balanced (barring a few exceptions like demoknight, or medieval mode/passtime/mannpower, idk). It's going to be felt in every single game mode because that's how the game is, and even though the competitive community tinkers with it via a whitelist and class limits, it's impossible to argue that the basic fundamentals of the game are "unintentional".
Yes, the balance of Specialists and Generalists is probably a pain, because there's a fine line that Sniper, Heavy, and Spy sit where if you buff them too much, they become overpowered/annoying, but I don't think this approach is necessarily a regret that valve has. It's very good game design to give players very strong but specific tools. The specialists are like your hail marys [edit: this term isn't exactly perfect for what I'm trying to say, but I hope you understand my point], great when utilized effectively, but high risk/high reward and designed to be switched off of when it is no longer appropriate. People don't run shotguns or forcebuy, etc. in competitive CS:GO full time, but it can be very effective as a surprise play, or when used in specific situations. Heck, the very nature of Spy is that he is a surprise, so running one full-time is not an optimal play. Valve did not do this on accident, I mean, we are all only here, 10 years later, because of Valve, even if you disagree with some of their methods, as I do sometimes.
There's just this weird stigma attached to players' mentalities that each class deserves to be treated equally, and I suppose it's because the base game's rules facilitate no penalties for such risky plays, due to the varying skill levels, but the classes aren't real people: they're tools, they're game mechanics, it doesn't have to be fair. Spy, or Engie isn't going to complain that he isn't being picked very often. The player has these tools in their arsenal, and it's important understand and to know that we have these rare, risky, and high reward options (and this extends to some of the individual weapon choices as well, like Kritz, Banners, etc., and even decisions, should the Demo bomb, should the medic go for the saw, should the scout hide here?), but that they aren't supposed to be run fulltime It makes for a fun and dynamic game, that is fun to play and fun to watch.
This is why people feel that it's important that Valve adopts some sort of accommodation to this understanding, especially to help newer players. But the game is so old now, and people--casual and competitive alike--are set in their ways.
I apologize for going slightly off on a tangent.