I honestly don't think it unbalanced anything. Looking at the results from back then I see a total of 4 IG armies (and I am absolutely sure that not all had Ordnance) and the best IG did was 25th. There were scenario requirements to deal with over-the-top armies and there will be those again this year.
I have run a few Combat Patrol tourneys/leagues to figure out how to deal with that

Honestly there are other many more pressing issues than Ordnance, and I agree that they will have a distinct advantage over certain armies, but than again, so will every other army there.
Combat Patrol is most of all a "fun" tournament and I would like to keep it that way
Cal