That may have done the trick but Davis and the Richmond govt. were operating on the false hope of other measures such as England joining the fight. It came closer than people realize. After the Trent affair there was a British plan put in place to arm (IIRC) 100,000 Canadian troops, ship over 10,00 British Regulars and invade the north. I believe they were also going to offer sovereignty (sic?) to either Maine or Massachussets (sic? lol) if they joined them. It also would have placed the British Navy in harm's way and may have (Possibly, even probably) broken the Union's blockade of southern ports. You have to hand it to Lincoln for smoothing things over before the British actually started these movements. For reference see Col. Robert Patterson's book DEO VINDICE. I believe you can still order copies off our 7th Mississippi Infantry website.
Another problem Davis and the Richmond govt. faced was the idea of arming slaves itself. Not the best idea for the safety of the southern population in many folks view. Remember the Nat Turner revolt and many other incidents of violence were not far removed from the southern mind. Indeed, John Brown's raid, credited by many as the match that lit the fuse to start the war threw fear throughout the south that the day may come when slaves, aided by outsiders would instigate a bloodbath.
I think it is wrong to judge Davis and the Confederacy for not freeing and arming the slaves early in the war. Basically the south had a tiger by the tail and had no way of letting go without drastic concequences. That is my humble thoughts on the subject. They aren't worth a nickel to anyone but me but I got it out of my system LOL!
P.S... Forgive my spelling but the wife is rushing me so no time for a spell check :-(