How Stampede of Goblins will work:
Players will complete missions to summon bosses. Once three different types of bosses are defeated the door to the Goblin Lair will open. Opening the door to the Goblin Lair will allow players to access more powerful bosses for a limited time. These bosses will allow players to gain higher ranking much faster, so opening that door is important.
Combat
Much like the previous event, Stampede of Goblins will be using a 10 card system. This means that to do the best you will need to have 7 strong cards and 3 Raider cards. Each time you attack you will use one of the combat resource, AP, of which you will be allocated 6.
Players can also use HP to do powerful attacks on enemies. As you defeat bosses you will gain Anima which will count toward your points as well as resources that can be traded in for cards, hp, cw, etc.
Rewards changes
Now, the rewards at the end of the event have stayed the same, but the event structure has changed by adding rewards to the middle of the event. The rewards in the middle of the event are made to help players compete during the 2nd half of the event.
This change is interesting because the length of the events has long been something that players have disliked. This mini reward in the middle gives players a shorter point to aim for, and the rewards will help them compete in the second half. It's kind of a nice break from having to push for two weeks.
It's also benefits mobage by making sure players are active early on. The earlier they are pushing for rank, the more HP they will theoretically spend.
The only thing I would hate of them to do would be to have the rewards at the halfway mark be weak event cards. Since these are supposed to be rewards for doing well, I feel that the reward cards should be decently strong.
Overall:
To do well during this event it's important to get raid cards and time your attacks. Since every attack will be using 1/6 of your total resource, it's important to ensure you're not overkilling too many bosses. Being able to calculate out your damage so you get the most bang for your buck is really important.
Outside of that, you need to open gates as well. Don't use HP before you open a gate. Since only one type of a gate boss will appear at a time, you want to demolish one, then do missions rapidly to get another up. Also, hit everybody's gate boss once for the critical bonuses.
Anyway, good luck and have fun!