After the election in May there is every chance that the First Minister will be Martin McGuinness. This is only possible in this election because of the actions of the DUP at St. Andrews. That is fact. Had they not changed the rules, the First Minister would remain a Unionist while Unionists were the largest delegation which is a near certainty in May. Now, the First Minister is nominated from the largest party.
Although there can be no question that the situation is entirely the fault of the DUP, they stand most to profit from it (considered by many to be the intention all along). Despite the bleatings from Alliance and others that Northern Ireland is moving on and people don't care about Green/Orange politics, for many, the sight of Martin McGuinness as First Minister will not be one they care for and is enough to sway casual voters and first time voters. The only way they can be sure to prevent this from happening is to make the DUP the largest party because the DUP are the only Unionist party that stand a chance of being so.
For Tom Elliot, this represents a real problem. He has no avenue of attack on this issue. He can not attack the DUP for changing the rules because it highlights to his electorate the issue at hand - that every vote for his party makes it more likely that Sinn Fein will end up as the largest party in the Assembly. He can't ignore the issue all together because it will appear he either hasn't got his eye on the ball or worse; thinks it a non issue.
The best Tom can hope for is that the DUP don't play on the issue which is only likely if they fear massive public backlash for being the ones to create the problem in the first place. As that is unlikely and any backlash will probably be tempered by a more stronger feeling of preventing the worst from happening, I think the DUP will play more on this issue the closer we get to May.