I've actually got some very specific points of constructive criticism on this iteration of the event that I hope SP will take into consideration for the next one.
There was A LOT of hate initially when this event hit. Honestly, I think if SP had released more info about how this one was going to work ahead of time, it probably would have had less backlash. Finding out there's a 50% chance when we were expecting 100% chance does hurt.
All that said, I think I'm ok with the changes they made this time, generally speaking.
I like that if you're using a combination that isn't one of the secret recipes, you get a clear message in the form of Treezard. It leaves no doubt that this is a wrong combo. I do have a couple recommendations on that, though. First of all, I think a lot folks were unhappy at getting a completely useless Treezard that normally takes 15s to breed and hatch and now has a 2 hr breed and hatch time. This was not an issue that I had, but I understand why this irritated people. My first recommendation on that is to pick a monster that normally takes longer to breed and hatch. That way people don't feel like they're being cheated.
I'm actually ok with the 2 hr breed time. Honestly, I'm using a fully-starred Breeding Guardian during this event, so it's like 23 minutes with that thing active, so I'm fine there. I would, however, recommend reducing the hatch time to 1 hr. To this day I despise the increased gem cost that was implemented some time ago for hatching speed up. Just make it a 1 hr hatch time.
Ok, so this is one that rustled some jimmies. It wasn't the monster choice or the breed or hatch time, though. Rather, it was the reduced chance of getting the monster (now down to 50%). I totally get why SP decided to do this though. Previously, if we had a wrong breeding combo, the result would be whatever those monsters might normally breed, with its corresponding breed/hatch times. More than likely, whatever was being bred was more than 2 hrs to breed/hatch. Reducing the wrong combo means being able to get to correct combos more frequently. So to balance it, they made the combos have a 50% chance. Like I said, I get it.
A couple recommendations. First, same as Treezard, reduce the hatch time to 1 hour. Second, increase the chance of getting the targeted monster. Maybe something closer to a 75% chance? As the day progressed, fewer and fewer players were willing or able to experiment to find more combinations.
Firstly, I love this event. It was a wonderful idea and I appreciate SP doing this and I look forward to the next one. Also, if we're going to get a result like Komocat and Treezard (to let us know about the correctness of combos) please get all other options removed. Breeding any 2 legendaries has a small chance of any common. Which is fun and games until you breed a genie. Not fun in this event. The only other constructive criticism I can think of: if you're going to change up the mechanics of this event for the next occurrence, please give us a heads up. Just a day or two. So we don't feel like the rug is pulled from under us.
Oh and give us a permanent storage solution! Need a place to store all these new monsters!