And hitting it? Do you guys remember in book 11 when the Animorphs fly the bug fighter? They're seen, and the military scrambles jets to intercept, and then in the bug fighter, they just take off, out of the atmosphere, so fast the jets don't even have time to react. The bug fighter they fly in book 45 behaves in a similar way, but is also capable of traveling underwater. At well over supersonic speed, I might add. I mean, that's speed and maneuverability (and durability) that even the best missiles of today can't come close to matching. And those bug fighters are about as aerodynamic as a brick. If the Blade Ship has similar capabilities, there's no way you could even hit it with a nuke (nukes aren't exactly the pinnacle of maneuverable missile technology), and even then its shield strength is up for debate. I don't think humanity would have a chance of surviving an open war. Avoiding the majority of people becoming infested, maybe, but at the cost of the entire race, one way or another.
As for the handheld Dracons- maybe that's all they need. Think about it- if you could keep the design of a pistol, but incorporate all the accuracy and stopping power of a rifle, you'd probably take the smaller gun, right? It seems to me that handheld Dracons far outclass anything the humans can offer in the way of handheld weaponry- let's face it, you're not going to be vaporizing people with no ammo limit if all you've got is an M16. Why bother with a big, clunky Dracon rifle when the little handheld guns are practically too much firepower already?
I think the Yeerks would be stupid to face humanity in open conflict, but I don't think it's because they'd have trouble winning the war.