I’m not sure which sources you’re listening to or what sort of music you like, but clearly you’re not hearing what I’m hearing. I have the latest 2016 LCD-2F and I can tell you there’s none of the compression, lack of speed or poor vocal timbre you speak of. It is fast when it needs to be, the bass hits when it needs to, imaging and separation are superb - almost holographic, and the build quality is outstanding. Maybe I have a ‘unicorn’ pair, but it’s brilliant. Sure the Atticus will have its own strengths, as will the LCD. Clearly you’re not a fan of planars, but possibly you haven’t heard a good one or your setup doesn’t favour them.
Glad you mentioned this, and look forward to your comparisons between the two. I’m glad because I’ve just finished a week-long A/B between a friend’s 650 and my LCD-2 using my home setup and my favourite test tracks and the LCD trumped the 650 in every single department. Name it, the LCD-2 did it better, with more power, clarity, detail, but most importantly emotion and connection with the music. Now I don’t have tubes, and I believe the 650 prefers them, but I can only use what I have, and what I have makes my LCDs sing. Run them on tubes, especially OTL, and you likely won’t get the full benefit of their sound.
That said the 650 was impressive, especially for its age and price. I can see why so many still regard them as the gold standard of audiophile headphones. The LCD-2F is a big step up, however, and the Atticus will most certainly be one as well.