These terms can be one way to explain why something worked or didn't work so well. They are the options a team has when coming into the game. I personally see them as an after-the-fact analyzing tool, it can help break stuff down.
I would say that they have become less relevent, but not because they are irrelevant, rather because too many apply too often. A forward facing ship is naturally aggressive, because it has an easy time flying aggressively, but put a Hades/Artemis on it and now it is aggressive and passive, but Artemis also heavily weights into the control aspect. Your average Mobula can easily fit into all three playstyles. Goldfish and Squid can easily switch between aggressive and passive gameplay too if they have an ally that is able to compete in long range.
What's also to note is that teams at the time of this thread, people focused on one single strategy or used ships that are either the same or very similarto each other: Charges with double Pyra, camping with or slowly pushing with Junker/Galleon or double Junker, hardcore non-stop flanking or more a more vague example: engaging from safe distances with an Artemis on both Squid and Pyra, building up that poke damage, which is still the same base strategy on both ships.
As the competitive scene went on, teams started switching things out. For example: Pure double Metamidion worked well for a time, but you risk getting easily shut down, so double Pyramidion teams decided to have one Pyra be some form of support fire, either via disabling/slowing down their enemy's movement to give the kill ship as much advantage as possible or via helping breaking armor and hull from a much safer distance, a different angle, making it much for difficult to shut both ships down at the same time.
Some of the support Pyras turned into the Goldfish, Hwacha and Heavy Carronade. During that, Mobulas kept coming up, fully replacing either the kill or support ships. With five forward facing guns, the Mobula had enough options to fit the loadout of two different Pyramidions on its ship, massively increasing the available options a team has mid-game, mixing in all sort of playstyles. After the Metajunker made the Hades/double Art trifecta so famous, people quickly found it easily fits into the Mobula. At that point, the Mobula, as a single ship, had the ability to use the playstyle of two different ships, had the superior long range firepower from the Metajunker, is a forward facing ship so can easily switch between flying aggressively and passively and had the highest vertical mobility so one had almost no chance of beating it in brawling either.
And that's about it, really. Mobula > everything cometitive did before using the Mobula.
(tl;dr:) So I guess what I am trying to say here is: With the developement of the meta, the classification of major and minor playstyles has become difficult to apply since teams started bringing ship compositions that can easily change to a different playstyle, on the fly. The position of the gun on the ship (left or right, who shoots it) and ammo types further blur the lines between those playstyles, which are only made a bit more clear again by certain maps when put against very specialized teamcomps, which would then get countered by other specialized teamcomps, making this classification system a bit more relevant again.
Speaking of applying multiple playstyles at once, boy, do I have a treat for those that are actually somewhat interested in this kind of stuff.