Saevel is pretty much spot on, the only issue I see is in the motivation for why they would do this.

To be sure, limiting each actor/Object to one pending action greatly reduces potential server load, but it also reduces the propensity towards abuse of the system. If anyone remembers extremely old-day FFXI, there were plenty of issues regarding item duplication and combat system abuse that spawned from more relaxed action delays and action rules (We could NEVER do more than one thing at once, but we were able to do things more closely together).

People were able to check their delivery boxes multiple times in rapid succession and duplicate whatever items were being sent to them. Trades > Disconnects were used to duplicate items, and even the old Disengage/Engage trick worked back then.

The combat engine limits players to one action at a time for both practical and preventative reasons. And no, I don't need access to FFXI's server source code to know that. What, do you think Astronomers go and put the sun on a scale to figure out how much it weighs? "Hurr Durr you don't have the code in front of you so you can't make experimentally sound assertions based on experience with other game code bases" is like saying that the sun could be made of cheese because we haven't been there and tasted it.

Mana seems to be talking about "Coding" in a vaccuum. Sure, I could go write some random pseudo-code to emulate FFXI's combat system and then add in a few lines that would make it work this way. But that's not how large-scale server-client processed MMOs work. Games run on engines. Engines determine what can and can't be done. This is not a matter of PS2 limitations, this is a matter of "The Engine was designed to do this. It can't do that. We would need a new engine and a completely new combat code base in order to account for that."

Why a new combat base? Because once certain, immutable rules are put into place, they are assumed when writing any other piece of code. All good programmers are lazy. If there is an innate limitation placed on the combat engine that prevents actors/objects from performing more than one action simultaneously, then programmers will not need to account for multiple simultaneous actions in any subsequent code. They can safely assume that everything will work one action at a time, because any multiple action commands are already tossed out by the server.

This means that removing that assumption will essentially break any code that was written with the assumption in mind. This would affect not only player characters, but monsters as well. Hell, monsters in particular. At least players have TP limitations. Monsters with regain/infini-TP could theoretically use an infinite number of TP moves simultaneously if they were to suddenly replace FFXI's engine.

Honestly, I don't really give a damn if I seem like I'm stifling creativity. When you ask for the impossible, someone is going to have to step in and tell you it's impossible at some point lest you all cream yourselves in some self-appreciating circle-jerk of ignorance and bliss only to rage and moan that much harder when SE either never responds to such a blatantly impossible request or tells you that they won't/can't do it.

I'd rather tell you up front that you shouldn't get your hopes up than have to deal with the river of tears that will ensue if this thread were to continue and be either ignored or answered (it's a lose-lose).

If you want to be creative? Fine. Just don't waste your infinite creative juices on ideas that will never, ever see the light of day in this game. You're better off coming up with shit that will actually work.