Now that I've hit rank 15, I think my main beefs with the instance overall are:

-Castrum pops too infrequently and the one minute registry period is way too short; particularly when you have no way of knowing when it's going to pop.

-You should get additional priority whenever you fail to be queued for a solo fight because in the current state of things you can realistically go days without getting a chance to participate in one. Better yet. they could just keep it active for a duration and let every qualifying player get a crack within that timeframe one by one considering how insanely easy it is to die.

-Memory drop rates need to be significantly higher so people grinding relics actually have a reason to be in Bozja once they've finished the quests needed to progress the relic.

-The total lack of scaling on skirmishes means some of them get melted in literally seconds by an only moderately sized group which makes grinding feel like a mad scramble even if you're focusing only on one section of map.

-The unavoidable mettle loss from death discourages people from participating in "hard" critical engagements; particularly Castrum because it penalizes you even more for both types of mettle loss plus you'll most likely have to return to base after a wipe.