If we want to continue playing 3-5-2, we then need wing backs who can cross and contribute offensively. That would mean getting a new LWB (we need a LB anyway) and an upgrade on Lichtsteiner who sadly, isn't good enough offensively. I hoped Isla would be that player but I'm losing faith in his future here.
If we don't have wing backs who can cross and contribute offensively, then by all means we should switch back to the 4-3-3, which I'd like.