I personally think it makes things more interesting and tests your raid's ability to adapt.
Exactly. Although this is only on 10man, we've had similar situations in previous raids, a particular encounter comes to mind, Halfus Wyrmbreaker in Bastion of Twilight with the RNG combination of dragons that you could get every week.
I think this added layer of complexity is a really fun thing to have because, although it’s still the same boss, you will still feel somewhat challenged for a few more weeks, there’s still some extra thinking to be done when you thought you had already “mastered” the fight.
You enter a raid each week without the absolute certainty of what exactly you are going to get, I enjoy that, the unknown always seems much more exciting than absolute certainty and routine to me.
When raids go into farm status you know exactly what to do, there’s rarely anything unexpected going on except maybe for heavy RNG fights and the only interest that will remain is loot and meter competition, anything that extends the “fresh” feeling of a raid without making use of excessive difficulty that will only cause players to feel like they’ve “handled the tactic but they’re hitting a brick wall” is, in my opinion, always a good thing to have as long as all possible combinations are doable at around the same difficulty level.
Now, don’t get me wrong, feeling that you’ve mastered something is great and we don’t want to mess around with that, we’re not adding RNG combinations to every boss, and even for those where we do, the number of combinations is not that high.
We want players to feel challenged and engaged by raiding, ultimately all we want to do is to provide real entertainment value, and in my opinion this is a good way to do it without overextending the time that is required to complete a raid every week, this way the number of bosses remains constant and the excitement is still there.
Of course we know that perfect balance is something nearly impossible to accomplish, but all the RNG encounters are designed to be beatable by the same raid group under the same circumstances, so if you feel that there’s some huge discrepancies in terms of difficulty between different combinations, we’ll take that feedback to the devs, who are always ready to perfect their baby.