Disclaimer: While I'd consider myself very strong with NFL and MLB uniforms, objectively, I'd consider my fluency in NHL sweaters as "I'm interested in them." If any of the below is incorrect, PLEASE correct me in the comments or Twitter (@dancfuller).
In the online uniform-enthusiast world, like any exclusive club, there's a vernacular in order to sound cool and avoid excessive typing. "BFBS" (Black for Black's Sake), "NNOB" (No Name on Back), and many more. There's also what's known as the "fauxback." It looks like a throwback, it smells like a throwback, but..wait a minute, has the team ever actually worn that uniform? Notable examples: The Minnesota Wild's Maroon jersey, the Avalanche's 3rd jersey from 2001-2007. Keeping it close to home, the Phillies current alternate uniform could even possibly be considered a fauxback, taking the 1946-1949 uniform, but dropping in the current "P" logo, wordmark, and typography and swapping the Red socks (for the few players that wear them) for the original Blue. All of that to say that the eagerly awaited Winter Classic jerseys are fauxbacks.
The Flyers actually don't have a particularly varied uniform history. Really. These are all of the uniforms the Flyers have ever worn through 2007. It's a cool picture which shows just how consistent the Flyers brand identity has been since their inception in the late 1960s. But, due to that rigid brand consistency, there isn't a lot of "flavor" from which to draw. It's pretty much "any colors you want… as long as those closers are Orange, White, and Black and in that order." Even the general design hasn't changed all that much: solid body color, accent colors on the sleeves, horizontal bar along the waist/hemline (depending on the specific uniform). It's a nice combination of elements: the colors are unique, the logo doesn't look out-dated, when they added a Black jersey in the 90s, it made sense given that that Black is actually one of their colors (see "Black for Black's Sake," above). But, unlike a team like the Penguins, they don't have some batty old "they wore what?!" type of design from a bygone era whith a completely different color palette to really get the fans talking. Instead, they made one up, and that's OK with me.
Without glossing over the finer points of what was probably an exhausting design exercise between Reebok, the Flyers, and the NHL, it's basically a mix of the current Orange uniforms (which trace their legacy from the mid-70s by way of 2008) with the jersey of the 1930 Philadelphia Quakers.
There is a collision of design language: notice the White nameplates and black letters, obviously lifted from the current Orange jersey (again, inspired by the mid-70s uniforms) as a sort of "it's good because it's loud and vice versa, and everything was ugly in the 1970s," and the Black triple-striping and shoulder panels borrowed from the Olde Timey Quakers design. This isn't exactly an example of picking the best components from different eras and combining them to make something better than the sum of its parts. But it works. Sure, it screams "HALLOWEEN!"… but it works.
Some commenters on Kyle's first thread were wanting to see laces on the collar, but there's enough going on with all those stripes and shoulder panels that they don't need any more design elements clogging up the top-half of the jersey.
For some interesting concepts, especially one showing a Flyers application of the currently trendy "logo in a roundel/seal" check out this thread on The Flyers Hive messageboard. Lots of interesting stuff there (especially the other pre-Flyers options).
Also, I pimp the Gridiron Uniform Database pretty hard for NFL games, so I'd be remiss not to point out The Hockey Uniform Database. which is just about as useful for ending fact-based arguments but starting subjective "which looked better" arguments as the Gridiron Database.