I think you see it more from people who play a lot of F2P games and then try this one out. It's pretty restrictive and some of the restrictions are just silly. I mean you're really going to ask people to pay to hide their helm or unify colors? Obviously that's not crucial to gameplay, but it's still a really petty (very EAish) thing to charge for. It's hard to go from a sub to preferred and still play this game.
You are ignoring a very important aspect though..... all of those features people carp about needing to unlock as freemium/F2P are all readily available for credits from other players off the GTN in this game.
Now.. for a brand new.. truly F2P account.. that's not easily in reach.. but for a veteran (not even a long in the tooth in terms of play time either) that wants to downshift from sub to preferred.. it's a cake walk these days. Seriously.. I've already got the "conversion kit" in storage on one of my characters that will unlock every unlockable feature or restriction and I purchased it all from the GTN. And I got them all at discount prices too as I was patient and shopped for bargains. This includes a boat load of 600K escrow transfers too (around 40 Million credits worth). So., while I plan to continue to sub, I can flip the switch any time and see almost no loss of access to features. The mail restrictions is really the only thing I would bump up against, and even that is manageable.
TL;DR the approach to freedom as preferred/F2P is a bit different in this game then other games, but it is in fact reachable without a long term subscription (2-3 months of sub, and moderate play, is all you would need) and no need for Cartel Coins either (other then to unlock Collections, which even subs have to do). You just need a plan and work the plan.. and you can flip over to preferred with almost zero impact.