It cannot be upgraded via smithing a shame though it is quite powerful as it is, but this means if you smith you'll always be able to create a more powerful weapon since you can get weapons up to ridiculously high damage amounts and armour defense too rendering you the ability to be invincible to one-hit everything on master difficulty and be invincible, so if you decide you don't want to be godlike then this is always a weapon choice, well it will be when they fix the bug where it benefits from one-handed enchantments... also someone told me it benefits from the one handed perks as well but still benefits from the two-handed skill as it goes up, I'm not at all certain about this but it could be true.
I'm playing a dual wielder at the moment and I've been using this weapon most of the time since my one-handers are boringly powerful and this weapon benefits from the one-handed enchants so I can still use it effectively, plus it's awesome and fun and increases my two-handed skill so I'll continue levelling and what not. In conclusion, cool but bugged weapon, hopefully we'll see a fix in the near future so I can make a two-handed user and use this weapon full time! I hope this answers some people's questions and if anyone has anything to add or corrections to make then I welcome them.