New content (stuff to do, reasons to play) is what's needed. The current mechanics you speak of are one way to get that and their presence should be praised -- kinda sad to see it criticized.
Never said that I don't want new content, on the contrary, I enjoy new content as it's stuff to do. Yes the mechanics are a way of delivering it and, when it's ALL we are going to get anymore, and in repetition SEVERAL times a year, that's my criticism.
Let's take a look in the past. Each year we had something new, at least once in the summer, and maybe for other holidays (not in any order): fellowship arc, fishing/pirate update, town invasion with lighthouses, town invasion with the 4 gods, shrine battles, exodus, halloween conj garb essence, shard of the dead, garg cure potion, etc. which were all mostly unique and had unique mechanics/quests associated with them. They were NEW and FRESH things to do. And we usually had somethings return ONCE a year, with minor additions, like Halloween in Doom and other dungeons. This is great, we got old stuff that returned, sometimes with minor twists/additions, PLUS new stuff.
So then why is it sad to see this new system of repetition criticized?
We will never have the interesting things we've had in the past. We are getting the same Champ spawn system that has been in the game for 20 years and ToT system that's been around almost equally as long. Don't get me wrong, ToT and champ spawns are cool and great, but my main issue is that that's all we're getting anymore and SEVERAL times a year. When the new ToT comes out that will be the 3rd in approximately 9 months and we're on the 3rd champ in 9 months... you get the point. We'll likely hit a 4th of each by the fall. Boring. Once a year should be the most for these.
So yes, I feel it's quite deserved a criticism at this point. If that's all we're getting, the same style 'events' over and over, it's depressing. Limit them to 1 a year and give us something new.
(notice my criticism isn't the new quest system itself, more that it's involved the pattern of repetition. Quests are great and I think we need more permanent ones)