Agreed on the 3 at the back point. If we aren't scoring goals then it is vital we don't concede. Playing Targett would likely be neutral: what we'd gain going forward would be offset by more defensive fragility. Plus, playing Targett implies we would get balls into the box, which is not effective as Wes cannot head the ball. So, not sure we would gain anything.
In saying that, though, the Arsenal game is a free punt (pains me to say that) where Smith can at least try and be attacking. At the very least he should play Grealish further forward. Sneaky suspicion that his approach is more 'solid at the back and score on the counter'.