As a matchday ticket buyer I've always gone to league games this time of year and gone to a last 16 or QF in the spring. The league tickets are so hard to get 2 or 3 together now, well be going to the Atalanta game instead and maybe the Shaktar, maybe there will be more that can't get to a league game and that will benefit the champions league games.
You're right and that is a benefit of some season ticket holders giving it a miss, it gives other fan's a chance to get to games.