Good question

Perhaps the core identity of the missions are the stages of improvement, if arena missions were to be last then that area of the game would be highly neglected from a progression point of view

in anycase thank you for your suggestion 

kind regards

In case you hadn't noticed post after post after post on this very forum ... I think you'll find arena  is 'highly neglected' now - or ignored by many other than for daily mission requirements -  because it's so broken. And it's 'stage of improvement' is so ridiculously out of sync with rest of the mission chain that it messes up progression anyway.

I hae been playing for almost 2 years and have not pulled the champions i need to Fuse Rhazin!  In the thousands of shards pulled so far, and so many dupes, where is Gnarlhorn, where is Erinyes?  Why are these not favoured in the shard pulls?  

I think this mission to fuze Rhazin is not fair at all.