It depends on what you want to accomplish.
Just saying something would be bad or good isn't always possible.
I can't necessarily say it would be bad. It certainly would be tough though.
There is a level of knowledge that the common citizen is not privy to. I believe Iran would be a pitched battle, moreso than Iraq. We certainly would win the major battles, but the guerilla war afterwards would be rough. We know a lot more about guerilla warefare in the middle east now.
Bottom line is we would win, but pay a price. We had better accomplish what we need to.