Again, I dont think Mo and Virgil are the issue. They suffer when the rest of the team is dysfunctional, as do all our top players.
The lack of midfield is hurting Mo attacking wise and makes our defense look much worse than it actually is, imho.
Mo and Virgil are issues though. Virg clearly isn't the same since the injury and we don't have the whole saving himself for the World Cup excuse anymore. Mo's form might be affected by the baffling tactical changes we've installed this season; making him hug the touchline to start off with, having a midfield that doesn't press etc, having a RCM who often takes up the same space as him in the final third.
That's why it's difficult to find solutions because so many things are going wrong. I do generally follow Woland's school of thought, that the squad is suffering generally from a lack of structured investment over the last four years. We should have shipped Ox and Keita out already when it became clear injuries had robbed them of the potential of becoming part of a settled midfield, for a start.