So, almost 6 month in... still a bad experience.
On the other hand, flying almost exclusively LH as SEN has been a blast. A lot of preferential treatment, regular upgrades into J, almost guaranteed free middle seat, getting drink service from J while traveling in Y, always getting the option I want when it comes to irrpos, much nicer hotel if forced to stay the night, very reponsive and knowledagble SEN Team on the German hotline, waitlist upgrades, access to F inventory and so on.
Not looking back. SAS is gone for me. Just need to see how to stay SEN. Quite hard when not flying a lof J. But I think I can make it.... but probably even just FTL is better than SAS crippled Gold-status which a subpar alliance.