For example, off the top of my head, here's a list of design problems that are fixed by 6.4:

• Semantically opaque * (and S) icons were used in all gamemodes. (6.4 solves this by using custom graphics related to the actual game role associated with each icon, e.g. a skull for dead players.)
• Icons were positioned inconsistently: in some gamemodes they were to the left of the name, in other gamemodes they were to the right. (6.4 solves this by making it consistent across all gamemodes.)
• Having icons appear on the right side of the name in the player list caused icons to overlap the roast/gem/etc. numbers, especially with wider icons. (6.4 solves this by placing them on the left.)
• Having icons appear on the right side of the name in the player list makes them difficult to find quickly, because they could be at any horizontal position on the screen. (6.4 solves this by placing them in a more consistent column, and the test builds even moreso.)
• Mutators had no way to assign icons to players, forcing reliance on awkward tricks like inserting the $ character into players' names, editing players' chat messages to insert an artificial * at the start, or drawing an entire separate player list on the screen just for the mutator. (6.4 solves this with the jjPLAYER::iconSet method.)
• Having an orange * to the right of your name would recolor your colon in chat and look especially silly in team chat. (6.4 solves this by having the icon be drawn separately instead of as part of the name itself.)

Here are problems that have been alluded to in this thread:

• Too much horizontal distance between the right side of the icon and the left side of the player name, making it faster to identify a player name than it used to be, but still slower than it could be. The test builds have been focusing on addressing this issue, and everyone seems to be on board with the direction that's taking, but there's still ongoing discussion about how to represent that a player is a Remote Admin.
• The * sprite is 10 pixels wide, but the flag sprite is 14 pixels wide. Kev says some players object to this--possibly because it takes up too much screen space? SJ says the flag sprite is perceived as alright. Not sure what to do with that discrepancy. Would a 10-pixel flag sprite be better? Did people change their minds about not liking it? Unclear at this time.
• The spectating eyes are redundant because spectators' names are already darkened. This is reasonable, the test builds remove the eyes.
• Kev has doubted that it's useful to see icons next to players' names ingame at all. I'm pretty sure it is useful: this is the way you tell when there's a flag carrier on your screen.

I may be forgetting something--let me know--but there are clearly stated reasons why these might be problems. It seems like it should be possible to get to a final design that solves all these problems so everyone is happy and nobody needs to use a "classic" design with a lot more problems. Clearly stated reasons like these are much easier to work with than a general sense that some people dislike something.