Whatever they do I hope they design the relic path to be casual targeted next time (target audience that isn't "lets do old school mmo mechanics" which I'd argue isn't the majority casual audience, but does have an audience who does appreciate this concept). Bozja isn't terribly hard, particularly the parts that are for relic given the perfect storm (if you have the number of people and the jobs / actions, but that's "given the perfect storm"), but the systems behind bozja are not casual targeted in so much that like forming a group and that group having a very real chance to fail (look at DF, the most common content for DF is content that you really only need like 1/2 to 1/4 your group even 'sort of' paying attention to complete), tweaks to spell and farming gameplay loops, etc.
I think they could keep it within a Eureka like content if they wanted but they should ensure whichever parts relics touch are targeted towards the casual audience (first and foremost, then build up for the other audiences from there). If Relic has to be extracted from Eureka because they can't do that, then fine, if they can then fine. People who wanted that old school era vibe may not appreciate shifts though (if say next Eureka was further made more casual friendly). So there will be some who win and some who lose. Whatever the case I think relic should be for "casual's end game" (meaning bite size, frequent and relatively consistently easily obtain-able progression steps, which may take a while- like some of the previous relics). Where there is then savage and ultimate for the determined / hardcore. Although like I said in other threads I wonder if simply just making CLL scale (so it's consistently progress-able with a diverse number of players and situations), making some tweaks to mettle loss (as to not turn a failed run into "I only took steps back today, today was a waste of my time" and logging off with little time a player had to give with disappointment), and creating a spell encouragement system could be the 'enough' for a larger casual audience (spell encouragement systems could be like DND spell rest system, or Dark Souls bonfires, or like FFIX or FFVII 'learning' systems).