There seems to be a lot of misconceptions being thrown around in this thread.
It comes down to whether or not you want to emulate as close as possible how gameplay feels on the original server.
I have a feeling most of the people who didn't move to anti-lead servers either didn't know about it, don't understand the changes and feel cheated, or found out they weren't able to compete on that playing field. Before anti-lead was out I never saw anyone complain about being low ping to someone. Playing against someone with single digit ping was the best experience on GunZ. Fights were quick and decisive, a single miss or mistake was less forgiving. Hunting down your single digit ping enemy in a 4v4 was chaotic but enjoyable.
In a straight comparison, aiming on an anti-lead server is "easier" than aiming on a lead server. Our lead server is the latency equivalent of projectile travel times. Projectile travel times would be like the rocket launcher in GunZ, the rocket has actual travel time to reach its destination. It is important though, to realize lead servers had a lot of artificial difficulty with leading. A few examples of artificial difficulty
*Ping is not always stable. This could be due to a bad connection or purposeful abuse. If someone's ping spikes they may seem to take more hits than normal.
*Managing players of different ping. If two players have drastically different ping, your shots have to be planned acoordingly.
Scenario 1: Player 1 has high ping and is playing aggressive trying to melee you while Player 2 has low ping and is shooting at you from mid range. Ideally you would shoot player 1 and put distance between yourself and player 2. However, due to player 1's high and possibly unstable ping, it is actually a better to choice to avoid player 1's melee threat and shoot at player 2.
Scenario 2: There are now 4 players on the enemy team with varying ping. You must match a ping to their name each time you see someone. This scenario can branch out but I want to keep it simple. You must now lead 4 players differently. You have to keep track of where the low ping enemies are, because they are the ones most likely to be shooting at you. "Focusing" players has a different meaning in GunZ. In other shooters, you focus fire enemies who are out of position or are an immediate threat due to their position. In GunZ, sometimes shooting at buddy with 200 ping and spiking just isn't plausible even when he's up your *** with his katana.
There are a bunch of other scenarios I could come up with, but these two get my point across. Leading shots takes more "skill" than aiming straight on. Having to manage enemies of different pings and plan accordingly for team games is artificial difficulty.
The problem only gets worse when you realize that people like to wear the same armor set as their teammates. Of course, that isn't a huge problem because you can still tell them apart by their names. Unless they have similar names. TWIN and TWLN look the same if TWLN uses a lower case L. What about names that are just similar? Superman and Suparmen? Demonslayer and Dernunstajer? Poop and Boob? Where do you draw the line for similar names? At a glance, they throw people off in game. You can disqualify players from using similar names in official tournaments but are you going to ban them when they do it in regular games? Imagine the previous scenario except with 4 players with 20, 60, 100, and 140 ping named TWIIN, TWIlN, TWlIN, and TWllN.
*Lag, potshotting, and backpeddling. Potshotting and backpeddling are valid and useful tactics ingame. You could argue that its imbalanced or overpowered but that is because the popular game mode in GunZ is team deathmatch. That is off topic though and I'll stick with what I was going with.
When two players with low ping play each other, backpeddling has a smaller effect on the outcome. When two players with high ping play each other, the winner is usually the player who can backpeddle and bait their opponent more. This isn't a baseless conclusion either, its game theory(snort; pushes thick glasses to face; eats cheeto).
This example is a bit hard to explain in words and is easier to show with pictures. If someone requests it, I will draw a **** mspaint diagram.
For simplicity, I am using time in seconds instead of ms, assuming dashes take about 1 second to complete, and assuming both Tom and Bob are of equal skill with perfect aim. Tom and Bob have a delay of 1s to each other. They are both using standard 1 v 1 gear. At time 0, both players are standing still 4 dash lengths (DL) apart. If both players move in parallel, that is, strafing side to side, there is no issue. That isn't the case though. At time 1s, Tom shoots then dashes backwards. Bob shoots then dashes forwards. It takes 1 second for their shot to register on each others screen. At time 2s, Tom's shot hits Bob. The distance Tom's shot travels to reach Bob is 3 DL because Bob dashed forward. Bob's shot hits Tom. The distance Bob's shot travels to reach Tom is 5 DL because Tom dashed backwards. Keep in mind that distance matters in a fight with shotguns because shotgun spread differs with distance. At first it doesn't seem to make sense. Then you realize it does because of how latency works. The shot originates from the location at time = 1 but reaches the opponent at time = 2.
You can call it skill but I'll add on that it's a broken game mechanic. Many players don't know how this works so they conclude "potshot and backpeddle is lame" without knowing the details. In a 1v1, 99% of the time it is disadvantageous to dash forward. 99% of the time it is advantageous to dash backwards.
Potshotting works the same way. You can't lead someone going behind an object. You have to prefire so you hit them when they come out. This is assuming the object is a pillar. If someone potshots and backpedals, they become even harder to fight in a straight 1v1.
*Behind-the-wall shots happen at very high pings but its balanced out better on anti-lead than lead. The scenario with Tom and Bob is no longer valid in anti-lead because even though it takes a second for Bob's client to register Tom's shot, Bob's position at time = 2 is irrelevant to the equation. It gets a bit complicated when you consider two moving players at high ping because they don't see the exact same game. You can see what I mean by comparing two replays of the same game by two different players with varying pings to each other and anyone else in game.
On lead servers there used to be a very popular strategy involving players from different locations. Essentially, the higher ping players play more aggressively and force close combat fights. They are hard to lead and recoil due to their high ping. It wasn't a game breaking strategy, it was definitely beatable but the fact stands that such a strategy should not exist. A good player who already knew how to be a threat with aggressive movements and positioning was even more effective with high ping. On anti-lead, you can't designate your high ping teammate as the "tanker" because he's just as easy to hit as anyone else.
*The sword aspect of anti-lead is an important thing to consider. I think, for balancing purposes, all melee attacks should still have to be lead. It may complicate things but unless there is a range limit we are going to see long range slashes, which are a huge problem. Back when anti-lead was in its testing phase, it was not uncommon to see a player lagging and slashing people from across the map. The worst part was that since getting slashed causes your character to "flinch" you could get flinched when you thought you avoided the slash. I think most sword enthusiasts will agree that they prefer slashing and blocking to be lead than anti-lead.