Proposed National Guard for Sunni provinces shrinks to 40,000. So what?

Reports this week indicate that the Sunni Arabs' share of of the National Guard will be 40,000 out of a total force of 150,000. This is perhaps the third time the number has been reduced. I recall a few months ago the numbers floated were around 50,000 Sunni Arabs out of total of 120,000 (the other 70,000 being allocated to Shia provinces). Going back to September 2014, the original idea was to create a local paramilitary force through which Sunni provinces can take charge of their own security. A Shia component did not exist in the original concept because Shia provinces did not have a security crisis.

It's been a thorny issue, and Parliament has not managed to pass a national guard law. Translating the idea into practice has faced great opposition by Shia hardliners in Baghdad who probably view the idea of giving Sunni Arabs a role in security as rewarding untrustworthy actors for bad behavior. However, the government, with a lot of prodding from the US, has allowed the arming and training of some thousands of Sunni tribal fighters. Some of those took part in the retaking of Tikrit back in April. And reportedly five battalions of Anbaris are preparing to hold ground retaken by the Iraqi army in the ongoing battle for Ramadi.

Sunni negotiators are said to be satisfied by the 40,000 figure agreed to with PM Abadi. But many questions arise: Do these negotiators speak for the majority of Sunni Arabs? Will 40,000 enough to provide a sufficient force to augment the Iraqi army in retaking Mosul? More importantly, will this deal be enough to give Sunni Arabs the reassurance they've been seeking?

The list can go on, but perhaps the most important question is this: What needs to be done to soften the Shia hardliners' (and Iran's) opposition to allow a meaningful National Guard to happen?