Wimbledon were bombarding Notts box with long balls/long throws all game anyway. For them this would basically be do plan A better. No way they would have switched it up and played possession football if it wasn't working for them, which would be legitimate plan B.
Whichever way a manager turns it's a stick to beat him with. Look at Amorim at Manchester United, he sticks Maguire up front for the last 5 minutes and gets criticised either for not having a different plan B (when it does work) or not doing it sooner (when it doesn't).
Maynard did try different things. 3 changes at half time Vs Salford. Playing Bedeau as wing back away at Port Vale to get more physicality in the side as two such examples. Unfortunately it didn't work out when he tried it, which may explain why he stuck to what he believed in.