Thanks for those links, Kulverstukas. (The Google translations are hilarious...)
Regarding the videoed dutch-roll incident, you mention crossed-wiring in the EFCS. We can presumably rule-out that being done at Sochi.
Re EFCS, I think this aircraft design predates fly-by-wire flight control systems, so we are simply talking about a dedicated yaw-damper system. Most if not all western swept-wing airliners have had yaw dampers - certainly since the 1960s. No doubt some need them more than others. The anhedral of the Tu-154 is said to reduce the tendency to dutch-roll, but it would be interesting to know how the aircraft behaves in the absence of yaw damping.