People think Phinigel was wildly popular because it was the first truebox server, but the reality is Phinigel was successful thanks to the Agents of Change that were added (ie. raid instancing). Players recall playing on Ragefire & Lockjaw and it was a nightmare with the box crews taking all of the lucrative camps, and essentially 1 guild taking all of the raid targets. A casual player had no hope of doing worthwhile content and they were justifiably upset.
If you recall as well, Ragefire & Lockjaw introduced pick zones (load balancing back then). However, they were only introduced in a few of the zones (mostly low level zones to help the initial levelling rush). This was the list of zones they introduced "load balancing" for:
North Qeynos
Surefall Glade
Qeynos Hills
West Freeport
Commonlands
Nektulos
Misty Thicket
Everfrost
Steamfont Mountains
Greater Faydark
Butcherblock Mountains
Innothule Swamp
Toxxulia Forest
Paineel
Field of Bone
Consider the above list, then consider a zone such as SolB. Good luck getting GEBs when there is only 1 version of the zone. I think it was Midgetts who essentially claimed this camp for himself and was even selling the rights to hold it for him when he wanted to sleep.
Anyway, eventually they opened up the zones available for "load balancing" and most zones became available to /pick in. But it was too little too late, and so they launched Phinigel - truebox, with instancing (Agents of Change), and the improved pick zones. An unbelievable difference compared to Ragefire/Lockjaw and introduced a way for any type of player to experience all of the content in the game. Unsurprisingly, this server became wildly popular, and I feel like many people unfairly attribute the success of this server to the truebox code, and ignore the other quality of life improvements the server brought.
I also feel like the Devs attributed far too much of the success to truebox, as every progression server since has implemented the truebox code, save for Rizlona. I think if Ragefire/Lockjaw had launched with Agents of Change, history would have been rewritten in a much different way. For better or worse, here we are, with people haunted by the memories of Ragefire and a deep hatred of boxing.
It's unfortunate because I think people are getting tired of having to run multiple PCs if they want to box a character on a TLP. I for one enjoy 3 boxing. You can fill every required role with 3 characters and get a lot done, which lets you just hop on and play rather than rely on trying to find a group when you get on. But I am not going to keep 2 laptops closeby to do this anymore, it's just not worth it. I think a "relaxed truebox" server would be quite successful, and it's too bad they keep insisting on truebox.