I was in 5c water a couple of weeks ago with a buddy diving Tecline regs, I was using Apeks and a student Oceanic. All were rated for cold water use, only the Oceanic gave any trouble.
5C water is not that cold for any cold water design (unless very deep). Most likely the difference causing one reg to freeflow is in servicing and tuning the regulators. If you start breathing on surface with a regulator still in -10C air, any reg will freeze.
Now that I look at TECLINE V2 DIR set, it indeed does look like a very neat 1st stage with tidy hose routing.