TL:DR: I hear a lot of complaints from my guild and other players that delve rewards are too random and just not worth the time and effort. Something needs fixing.
Okay, so we have delves and they are a cool idea. The one team, go as far as possible idea is great but there is a bit of a design philosophy issue I see here. For Raids and Invasion you can not “win” in that you never finish. You go as far as you can until you are out of seals or get your head handed to you in a bag. No problem, that is how they work, the rewards are solid for the amount of time and effort. If your team dies, no problem, you get another, and maybe get some pooled points (boss damage or towers demolished). All good.
Delves seem to be following a similar design in regards to:
1: They are limited like Raid and Invasion based on the seals you have.
2: The difficulty ramps up fast if you complete the highest level one you can do.
3: The turn into “go as far as you can before getting you head handed to you”.
The problem here is the point of the delve is to “win” or finish the boss mythic room. With the limitation on the number you can do plus the difficulty ramp + the diminishing rewards for doing lower level delves + random treasure pull at the end, this all = frustration for the players. Getting trounced by a level 140 Zuul is fine, is good, you can still contribute and get goodies for it. Getting slapped around like a red headed step child in delves is an exercise in frustration that turns into an exercise in “why bother?”.
So, what to do about this. I think the rewards structure and the diminishing returns needs to be revisited. So, some possible recommendations:
1: Delve fights give a little faction based on the room level. Not much at all, maybe 1-2 faction points per level of room. At least you will get the feeling of progress, even if it is grindy.
2: Random diminishing returns vs. non-random rewards structured to level. Okay this is something that is really at the core of what I am saying. If the rewards were non random, or less random and structured to level instead of a random pull that gets a nasty ding if you do a “lower” level again, it would give the player the feeling of progress, albeit slow. How could this be done? Well, say for a level 50 delve you are going to get the FP from clearing the rooms and X chaos shards based on the level of the delve, for instance, level*0.5. Then the level of the delve chest would directly pertain to the random treasure bonus you get for finishing the delve, higher possibility for rare/ultra rare/legendary/mythic treasures, bonus FP and bonus chaos shards.