I think it has been clear that Raf and his design team are trying to move Jil Sander into a more arts-y, cerebral fashion context, in which designers such as Yohji, Helmut Lang but also Alaia definitely have been reference points in seasons past... this works out fine for as long as he manages to channel these aesthetics in a strictly realistic 'Jil' frame of wearable garments with incredible architecture and cut, but that customers can easily envision being worn at any time (as you were refering to in the Yohji coat example).
....Similarily, I approve a lot to Theyskens latest collection for Theory - it's done him good to take the challenge and distill his design to the core, not only price-wise but also aesthetically, it feels very direct and honest to me, which I like.
I very much agree with you - I was expecting much more from Raf as his roots are in menswear and he has shown a huge diversity of design, experimented with materials, shapes and proportions, even much more than Slimane. To design JS day wear should have unleashed his complete creativity without being constrained by the demands of menswear - he would have much more to "play" with.
Most of my clothing budget goes to good jackets, coats, pants - these are the pieces that are very difficult to design well, yet these are the pieces that are staples in most wardrobes. I don't know about others, but when I have a favourite which looks great, I'd be terrified of damaging it and I'm likely to buy more in different shades. This was what I appreciated about Jil Sander and Yohji - they do it differently from the average designer - the Agnes B., the APC, etc.
It's perfectly fine to send out couture-shaped dresses and skirts, but there's got to be more thoughtfully designed jackets, suits, coats, the hallmark of Jil Sander, the reason most JS customers turn to the brand.
But of course now there's Theyskens' Theory to fill the void.