Spe0I think its time for the competitive community (more specifically 6s) to take their blinders off and finally admit that the reason why there is a "bridge" to be built or that there is a gap between the casual and competitive community is entirely because the casual community is filled with people who main or primarily play pyro/spy/sniper and would like to play their main classes in 6s full time but are fundamentally barred from doing so.
My wish for a promod (if anyone wants to build a promod) is to take this reality into fact and aim to "generalise" the "specialist" classes so people who want to play these classes full time can do so without ruining the aspects of 6s that makes it so great. There is a fine line here, as the promod should aim to both keep the identity of these classes intact and also make them work in the core 6s gameplay loop without slowing or "hero shooter"-fying (i.e damage sponge galore) the game.
A 6s gamemode where 9 out of 9 classes can be ran full time opens the door for finally unifying the HL and 6s community as there would no need for a gamemode that specifically caters to offclass mains, adding in tons of players who are invested in the same game and the same scene. This would bring more life to this dying game that any "tutorial " or "QoL" change can ever hope to bring
Making pyro, spy, and sniper more generalist means that they wouldn't be pyro, spy and sniper anymore.
Making the weak classes significantly more viable than they are for 6s would require fundamentally reworking how they're designed: you'd either have to (A) make them bad imitations of the fragging classes in order to retain their specialist niche, or (B) weaken their specialist side in order to strengthen their generalist side, which is the same as removing them from the game. You can't keep what's good about a specialist while making it on par with the generalists at the same time; that's like having a scout that can airblast. At the same time, if you try to "balance" this by reducing a specialist's advantage, the class literally no longer exists. It's like saying, "Americans can become more successful by acting more like South Koreans." Well, we wouldn't really be Americans if we acted like South Koreans, would we?
The reason the generalists are good is because they are effective at both offense and defense, and at both long and close range (or midrange). Soldier's ability to bomb and scout's speed make them stronger at long range than they first seem. A class is a generalist if it's good at these four things, and a class is a specialist if it's relatively bad at one or more of these, but particularly good at one or more of them. Heavy, for example, is weak on offense, strong on defense, weak at long range, and strong at close range. Now, imagine what you'd have to do to make heavy a generalist: you'd either have to make him better at offense (faster, more mobile, harder to hit) or better at long range (increase damage significantly at range, faster). If you did this, it would look like you're playing heavy, but you'd actually be playing scout. You'd have to make heavy light, which violates his design.
One thing that TF2 gets (almost) perfect is how attacking and pushing is generally stronger than defending and holding. Many other games get this wrong, and the best games (e.g. basketball) get this right. The new config for 5cp was an additional improvement in this area. If defending (or not attacking) is stronger than attacking, the game grinds to a halt and becomes boring to play and watch. In addition, attacking (in any game) is generally regarded as being more complex and having a higher skill-ceiling compared to defending. This is why "camping" has a bad reputation in some games; it's why the best Counter-Strike IGLs set themselves apart with their T-side calling rather than their CT-side calling (e.g., Karrigan on T-side Mirage); it's why the phrase "the best defense is good offense" exists in military strategy and basketball; and it's why the famous military theorist Carl von Clausewitz said,
"What is the object of defence? To preserve. To preserve is easier than to acquire; from which follows at once that the means on both sides being supposed equal, the defensive is easier than the offensive... as the defensive has a negative object, that of preserving, and the offensive a positive object, that of conquering, and as the latter increases our own means of carrying on war, but the preserving does not, therefore in order to express ourselves distinctly, we must say, that the defensive form of war is in itself stronger than the offensive."
The reason most of the specialists (Heavy, Pyro, Engineer) have to be worse than the generalists, in terms of good game design, is because defending is in and of itself stronger than attacking. Defenders get to sit back and let the enemies walk into their crosshairs, they get to hide in safe places, they get to focus fire a single chokepoint, and so on. In order to balance this natural advantage that defense has, and because defending is more boring and less skill-oriented than attacking, you make the defending classes worse than the attacking classes. Counter-Strike does this by giving Ts the AK-47, and TF2 does this, in part, by making the defending classes worse than the attacking classes in various ways. It's just good game design.