I dont see how you say you cna have no "animation delay" as this is just how these games work. The client only updates to the server with your position a few times a second, and then the server only tells other clients a few times a second. even with a ping of like 50ms, you are still talking about 250ish ms of lag between when one client moves, and another client starts to see them move.

there are 2 systems a game can use for lag management. one is the classic server side method employed by the older generation of MMOs, in which the servers opinion of where you are located is alwase right, and it tells both others AND you where you are located. This used to cause an effect called "rubber banding" where you would see the world jump back a few feet when a few packets containing your movement data were dropped(a common occurance, the internet isnt perfect). Newer systems trust the client to determine your real position. This means that where you see someone else is not nessisarily where they actualy are. The down side of the client side, is that it is both incredibly unsecure(all your location data is on your machine in your memory and is freely open to modification) and can cause uneven synch rates (every melee class has ecperienced a moment in battlegrounds where you are out of range even though you are standing right on top of the dude). The server side approach is much more secure but incredibly annoying for everyone. The client side is just better for the general populace.

also, there is no way to use regular movement keys. Any tiny deviation cause by a local frame being dropped will only be magnified over time. You may only be a fraction of a degree off center, but 500 yards down the road your 2 guys will be 20 feet apart. and there is no way to get them perfectly lined up again.