Making Duskblade more expensive (~3500g),

but adding armor to it, would be cool imho.

Something like:

60 AD, 30 Armor, same passives etc.

just so people can't rush it alongside a pure damage build but it's still a big item purchase.

Cost-effective armor items are hard to come by right now.

Or how about: 3300g, 55 AD, 25 armor. That's pretty unique for a statline.