On page 1, the report states:
The Iraqi people have a democratically elected government that is broadly representative of Iraq's population, yet the government is not adequately advancing national reconciliation, providing basic security, or delivering essential services. The level of violence is high and growing. There is great suffering, and the daily lives of many Iraqis show little or no improvement. Pessimism is pervasive.
So one question to consider is whether the ISG recommendation on military trainers would decrease or increase the level violence in the short term. On this point, a military analyst emails:
This business about increasing the number of embedded trainers (which the report explicitly suggests we do without increasing forces in Iraq in one sentence, even though it then tepidly endorses a brief surge in another), is extremely dangerous and seductive. The trainers will be advising Iraqis on combat missions. But 20,000 trainers means 4-5 brigades of our troops not conducting security operations on their own (out of 15 in country). That will be a big hit on security, since the Iraqi troops will not replace them on the streets quickly or with any degree of efficiency. This likely means a short-term surge in violence…. So I think that the report is in some respects more dangerous for being less bad than it might have been.