For me the annoying thing isn't that we couldn't switch to a Plan B so much as that we weren't even trying Plan A properly. Against Ireland England were moving the ball wide quickly to create the space in the backfield, forcing the backs to move up, and then kicking. It was exacerbated by their fullback issues, but that basic plan is pretty clever.
Wales were better at slowing the ball, so we couldn't always get it wide as quickly. This meant than there was more time for them to drift wide, and their backline cover stayed intact more often than not. Where I feel England (Farrell, and to a lesser extent Youngs) were getting it horribly wrong was that if you have a two-step plan (1. create space in the backfield 2. kick to the backfield) you don't skip to part 2 if you can't get part 1 right. (I wonder if France spoiled us slightly by doing step 1 for us?)
And I'm sure the point can be made that Liam Williams is a better Fullback than the others, but the fact of the matter is the tactic still worked! There's a few examples where we managed to draw him out of position*, and we pretty much always ended up in their 22 because of it. Because he knows what he's doing, there were fewer opportunities, but I would have liked to see England create or wait for those opportunities rather than just wellying it.
*Rewatching the game, I think at least some of England's shitty kicking was to draw Liam Williams up from the back so they could tie him down. Problem with that is it only works if you win the aerial battle, and Williams was very effective.
