I liked having to do the HM primals to get the relic. I did get the Zenith as well, and eventually an Atma, but I've stopped trying to upgrade it after that. I still think it would've been cool to just have the weapon itself gain experience points, and then you use those points to upgrade parts of it. Once at max experience for the iLvl, add a quest (kill x extreme primals, some instanced solo fight, or whatever else) to unlock the next max iLvl, and then go and get experience points for it again.