Alright, here's my my overall experience with this event and some suggestions.
I have set myself the goal to get 2 fully evolved bears (brow and panda) and I achieved that last night so now I'm taking it slow and the keys I get I will use to get some more boosters, kps and maybe one daily prize I like. I spent a lot of boosters to get the 18 atrifacts and most of all A LOT OF TIME, waaay more time than I want to spend on this game. I could continue in the same way and probably get the 3rd bear to lv 10 but I don't need it that much. What I need is to go back to a more relaxed tempo of playing this game. I would maybe be fine with spending this much time on events if there were just 4 big ones, 2 or 3 smalls ones and 2 or 3 FA like before, but at the rate they are coming it's ridiculous and I can't keep up.
I don't like the random quests at all. I loved planing for events it was my favourite part of the game and for me events will never be as enjoyable again unless they go back to the sequential quest list or at least a party sequential quest list as has been suggested in this thread.
I am not sure how I feel about the endless quests. As others have pointed out it allows me to win more than I would with the old system but at the same time because of it we have the random quests, the difficult repeating quests, the required workshop/T1 levels and in general the fun was sucked out of it. There is only so many solve 45/9 and gain 11 relics one can do before being bored out of their wits by it and quitting the game and those have been most of my quests since I got to the 80 keys mark. I have a smaller city in orcs and I haven't logged in for 2 days now bc I just can't get myself to do the same thing there too. I am seriously considering deleting it as this is too much work for me. So all things considered I think I prefer the old system with a fixed number of quests. I did win less but it was less stressful and a lot more fun.
Since we were asked to give some constructive ideas, I really tried to think of possible new quests and I admit it is hard. This game has only so many features and without introducing new ones it's hard to think of something really different and new. But here are the few things that crossed my mind.
1. Why don't we have combined quests? Like: "produce T1 3h x2 and advanced tools x2". or "gain 2 spells and 5 VV" Those are not really new quests but there are a lot of possibility to mix and match them so at least we wouldn't be seeing the exact same quests over and over again to oblivion.
2. Why can't the quests be different by chapter? We get buildings that produce different goods depending on chapter (supplies-T3-Mana-Seeds + orcs) why can't some quests do the same? I get that the event should be accessible to all levels and it still would be, it would just make it possible for advanced player to have more diversity in their quests and to put to good use some of their event buildings.
3. If the completely random system has to stay why not just use all the quests. Determine the value of each quest. So: give NHx3-10 key, produce 2 toolboxes -45 key, scout/tech/15vv- 80 keys , 25/5 encounters-35 keys, 45/9 encounters -75 keys etc... And we can get any quest in any order. If we get an easier one we get less keys if it's a harder one we get more keys. The evolution of keys doesn't have to be progressive. It can just be linked to the difficulty of the task.
That's all I have. I'm fully ready to hear some of you folks point out big flaws in my suggestions, and it's fine, I'm sure I'm overlooking something, I just wanted to make an effort to give some ideas and if they are not good, maybe they will inspire someone else to have some better ideas or build on these.
About the prizes.
The brown bear is great, I love it. I always struggle with troops and the boost it gives should make a big difference.
The panda... well the amount of T2 it produces is ridiculous but the special effect is actually pretty good, it gives me almost 70k T1 per pet food used. But ofc it's very costly: minimum of 2 pet foods needed and an effect of just 1 hour. So great if you need T1 fast but bad for your pet food supplies. I will probably just use it in dire need, and the rest of time it will be in my city for aesthetics purposes as I like a lot how it looks.
And the best for last. As always the graphic designers have done a great job. The bears are lovely. That is the one part of this game that is constant and hasn't disappoint me so far. Maybe not all themes are my cup of tea but they are all well done. I know that all of the daily prizes are recycled, I had most of them in my city before, but don't mind as they are really nice. I actually love that prizes are recycled now and then as it gives the chance to us players who don't get blueprints and lots of RR spells to get back some of the buildings we liked but had to sell at some point because their values were too low.