Oh, wait, it's actually because clients are impatient babies and want things done right now. (if you haven't guessed by yet, my job is in product development
)
That might be true. But as many times it's an issue of missing or bad communication. We could take this update as example. A simple "We tested the impact of higher levels on PvP and are confident this won't further affect PvP balance" or "We are aware of the impact this update might have on fort fights and duels and will further monitor and address possible issues"
Or "This is just the first step. We are already working $foobar".
Or "We will add new Quests for higher levels soon."
Or a gazillion things that could be said without overpromising things.
For sure people would still contest such statements and start arguing. But that is also a result of bad communication in the past. Like promising a "big update" and then being silent for years.