The thing is that last year song started that.
Song or no Song, the point is that with 2 DM's our midfield was horribly static and struggled to get forward. We tried to improve our conventional-bunker defending with two primary defensive players but instead that just got us pinned back and made us lose the proactive attacking dominance that masks our defensive flaws in the first place.
Masch isn't really technically superior to Song (better long balls) so nothing he provides counteracts the properties that screwed us over against Sociedad. The only difference is that he'd make less errors when we are pinned back and being attacked. Mind you, Sociedad last season was nothing compared to Valencia this year AND we had Iniesta playing who was in his very strong post-winter break form.
It could be different with Xavi and a better Messi but I'm holding my breath. We struggled to transition forward in the last minutes against APOEL with this setup as well.