Selling an unmotivated, now permanently out of form with us AS is good business if anything. Esp now with Cuadrado starting at RB. You can't have an attacking FB like AS (esp current version that can't defend) on the other side too. Asamoah almost played like a LCB with Cuadra at RB.
We did well forcing AS to stay last summer, but since then, with his permanent sulking and avg performances, it was almost certain already a while ago that he'll be sold. That's why that new contract wasn't signed either.
As for replacements, don't see anything panic-worthy yet. We need a Howedes clone, a fitter version, for LB with Cuadra at right. And an attacking alternative for when we need a goal and a Spina replacement (more attacking LB + LW reserve) with him practically out for the season (out for 4-6 months + will take another 4-6 months to get back to 100%). Bernat as that player suits perfectly. Better than Spina and this season's AS in fact.
Darmian as more defensive backup/reserve for both sides and MDS as more attacking one sounds fine. Darmian can play as CB, so can play that defensive FB role, and in that role his loss of speed won't be a problem either. Plus, we tend to return players to their best and get the best out of them.
It's a priority. We lack speed, dribbling, and counterattacking ability up front. We shouldn't be just addressing two of our needs (CM and FB), we need to address all three.