If we had good forward thinking fullbacks, I think we would be well suited to a 4312, allowing various permatations in midfield and upfront and providing Vigurs and McFaddden some much needed freedom.
Given the lack of mobility offered by Ramsden and Hammell though, I do think we need to consider moving to a 3412. I don't trust either defensively but ZFA and Kerr would offer some much needed pace and energy up the wings with Carswell and Lawson mopping up behind them.