Your guide is useful for a newbie and standard FL player to get a general sense of how to do well with a group.However, there's too many holes and flaws for an indepth understanding on how to improve further though (which I'd argue is probably important as players start to stagnate and think they can't win because they 'tried' all possibilities listed in the guide). Lots of points you mentioned aren't as set in stone or as good as you think they are because there's various ways people can tackle and take advantage of them. Lots of the cons you mentioned are standard cons that only apply to people who haven't developed a particular sense of gameplay style to overcome those weaknesses. In FL, where it's constantly chaotic and fast-paced with many different levels of skirmishes, there's many ways to mitigate and turn them into an advantage. This feedback is more targeted to solo play, as I've developed this understanding during my time as a solo player and can still win matches with this as a solo player when facing premades.
For example: SCH and SGE. You listed both of them as no CC and Squishy. That couldn't be farther from the truth in the way I play both of those jobs in PvP. Indeed, there's no hard Crowd Control effect listed in their skills, but there's more than one way to force "Crowd Control" without depending on solely the skill itself. That's where the differences in gameplay and mindsets between players start to separate the players who are developed their own sense of understanding of their job in FL -- grasping this point opens a whole new set of strategies when mastered, especially for each job. Is the innate job squishy? The answer - yes! It is. However, they're only as squishy as the way you play them. By that regard, every job can be non-squishy and very much lethal. That's how the top players in FL can have low or 0 death counts even when playing with a squishy job when they're a solo player.
For example ... there are times where an entire alliance would focus fire me when I'm playing SGE, and I'd survive after taking the hits of over 10-20 players because I make sure to utilize all my advantages of the job's toolkit to its peak. It isn't because I happened to guard and focused fired during that period. No, I forced that situation where I purposely place myself in a spot where I will take damage for everyone else. Is SGE still squishy? Absolutely. If anyone messed up in that spot, they'd pop. However, that doesn't change the situation where I have established to the enemy 'this sage is hard to kill, either needs a nerf or player is good'. At the same time... it's "Crowd Control", but not in the same sense as the crowd control from the game. It's crowd control via understanding your opponents to dictate their actions given what you can do with a toolkit. However, the implementation of these tactics are derived from the core concepts of the game mode itself -- baiting, diversion, aggro, line of sight. SGE might not have hard CC to lock someone in place, but it might as well be hard CC for me if I can divert their attention so they end up staying in place. Like every other hard CC, this kind of control can be easily 'cleansed' if people are aware what the SGE is doing, but knowing and grasping that opportunity is also a strength inherent to the player itself, and much less to the job. Again, this is a very high-end example, but it's something you might want to mention. These concepts can apply to Crystalline Conflict, but because the scope, players, and terrain is different, there's much more versatility for each job in Frontlines to take advantage of. If this sounds surreal, that's because you have to re-examine every job fantasy in the lens of PvE BLM and then take that dynamic gameplay a step further to find your own unique playstyle in Frontlines. Remember: DPS is important in PvE, but it's only one of the many factors to winning. Frontline's Player vs. Player's importance on DPS isn't so much on a static rotation. Damage is not the endgame, it's just a way to expedite the usual winning formula. If you can develop your own way to cripple this winning formula, it's no longer a winning formula.
This advice applies to every kind of strategy, premade or not.
As for commanding, each job has their own set of unique ways they excel and can contribute. Jobs with specialized effects and jobs with wide-area effects have different focuses when shotcalling due to this. If you want to follow the general premade set of strategies, you can use a tank like DRK as they are a strong 'CC initiator/disruptor'. If you want to create pincer strategies, hard ST debilitating jobs like MNK or WAR pull do well here too, and even counters DRK itself. Some players tend to be a better shotcaller due to playstyle, but ultimately shotcalling requires understanding more about how the map works and being able to take key information to grasp how the changes in the battle happen and to implement the next best strategy based on your job and your team's capability. Being able to understand how to effectively parse that information in a moments notice also drastically improves your ability in a fight even when you are no longer shotcalling. So even when I'm not putting as much attention or trying as much when playing casually, I've built up a certain level of foundation to be able to affect fights far more than other players can due to taking advantage in the difference of knowledge gaps, at both a map-level and fight-level standpoint.
In another and broader analogy, commanding is akin to playing a chess game. You are the chess master looking at how the pieces move and the strength of each relative position, but at the same time you are the chess piece who can directly create a new strategy yourself. A good chess piece who understands the chess master's perspective can perform to their fullest potential and also free a chess master's cognitive load by creating opportunities. A guide is ultimately a guide - static and dead. However, people are alive. Things can change as long as you know about it and act on it. Of course, the more chess masters there are, the spicier the game can get - and then it becomes a battle of wits. Very fun stuff at a high level understanding when you do notice all the unique strategies these players do. It's why premades -- while powerful, are still limited because they can only be chess pieces, and a chess master has many strategies to break them apart.
By that note -- For stuff like openings for risks as a commander, forgive my vulgar language - but it's a complete load of sh*t. Openings aren't really reliable at all because you can't expect to know what jobs and how skilled your opponents are upon starting the match -- which can have a bigger impact on whether the openings are feasible are not. It's more better to call those paths 'lanes' than 'openers' because you can use the terrain to give yourself an advantage and narrow/determine specific points of conflict even after the opener is over -- especially when defending nodes or fighting over nodes. At the very least, this is my experience from playing and winning games as a solo player. Hope this perspective helps people reading and struggling with FL by taking a new approach and makes the game mode more enjoyable to you. Or idk, gives you a new perspective on how high-level Frontlines work if you really want to win as a solo player.
This advice applies to every kind of strategy, premade or not.