Fantastic information here overall! But to the quoted piece, I'm going to have to say this is almost absolutely wrong!
I spammed frontlines for the allagan circle mounts, and I've just recently attained them, so I put in about 300 frontlines games in the past month. I main Dragoon and it took a while but I figured out how to do my role well, but I knew that even calling out ices and when to attack bases and avoid pincers etc. etc. I was still not carrying very much. And since Machinist starts at level 30, may as well try it!
So I swapped to Machinist and man was it easier. With my calls trying to lead the team and being able to range people to death, my win rate skyrocketed from ~30% to over 50%.
Proofs:
I have about 100 games on machinist and I played half of those without even thinking about reloading before battle and about half after seeing others do the same, with a little bit of back and forth trying to see what works better.
90% of the time, reloading before battle is better, and the reason is ice! If Gausse Barrel is attached and then reused, you instantly overheat (this has like a 1 or 2 minute cooldown), and you have 3 loaded bullets to maximize burst to take as many points as possible from enemy ices or neutral ices heavily fought over. So at 19:45 aim for ices that you can steal points from, and use your preloaded bullets to burst as much damage as possible to steal points. I don't know for certain but I'm pretty sure there's not a single class burst combo that can out-damage machinist over the ~12 second period he's overheated and using ammo while overheated. When I run my combo I will always have ice aggro unless the ice lives a while and the sustained DPS of a melee can eventually take over.
What if an ice spawns at 19:45 that is in your base or in an enemy base or somewhere you can't get points from it? You have two options: Wait for the big ice at 19:00 to run your burst or if enemies start sparring before that ice, you have the option of bursting a player down if you think you can secure the kill.
There are two not as common ways that this doesn't work out for you.
1) You decided to wait for the 19:00 ice but an enemy team came out aggressive. You may have lost points by not securing kills by not participating in the pre-ice brawl.
2) You decided to try to burst someone down but they had good healing support and/or you didn't pick a target anyone else attacked so you didn't secure a kill. Now you're gimped against the ice when it spawns.
Again, 90% of the time and learning good intuition with experience means pre-loading bullets before the battle starts is going to net your team more points, as long as you use those pre-loaded bullets to pull off insane burst by instantly overloading your gausse barrel.