I think it's the best system for out current crop of players. Our best central midfielders are all defensive. We have no traditional left-winger, except Eagle. Foran is more of a left-sided attacking-mid-***-striker* rather than winger. We've no central attacking mid, so have to play more lightweight players in there, like Sanchez or Odi, hence the further need for two defensive mids. But that also allows that mid attacker to get up more.
If we switched to 4-4-2, I don't think Foran would have the ability to play that left-mid position so effectively. He's far more a forward than midfielder or winger. I also don't think we have the passers in midfield either. Proctor, Duncan and Cox would be winning the ball but struggling after that. McBain could come in but I think his time is passed. This would be made even worse in 4-3-3.
Aside from teams that we might be playing for a draw against (I know we shouldn't be doing that currently but if it comes down to us only needing a draw in a tough match - maybe then), the only change I could think of would be going to a 4-1-3-2 system. Then I'd rather Foran up front than Eric, with the left-attacking-mid being taken up by Eagle or DZ. But, at the moment, it's stick to 4-2-3-1, especially away.
*ok, then mid-come-striker - by the way is hare's-tail cotton grass out yet? Y'know, Eriopherum vaginatum? Let's see if that makes it through.