Mid-September will bring us a new unlockable character unavailable to Duel Links as of now. Based on the given quote we can assume that the new unlockable duelist will be Yubel whose personality mainly revolves around her love for Jaden as its owner. Another evidence is the leaked Mat and Sleeve of Yubel - The Ultimate Nightmare.
Massive Update - 5D's World available on 25 Sept 2018
A New Development in Yugioh Duel links. This could likely be the addition of 5D's, the third series of YuGiOh into Duel Links like how GX was added late last year. With the addition of 5D's World comes the addition new characters, events, cards, and the Synchro summoning mechanic.
I doubt we'll get animations for most of them. Can you really see them giving an animation for Gold Rat or Freezadon when we don't have animations for cards like XYZ-Dragon Cannon or Elemental HERO Shining Flare Wingman?
will not happen because then people who used real money will complain. And there are many enough of such people, including popular ones, that will give a bad rep for konami if they complain.
Give us synchro's, more gx character and 5d's universe, we don't want more about DM that series was boring and stupid with A LOT of plot holes and stupid things like *time wizard being used as a spell card*
Ridiculous rules you said? Synchro is just white contact fusion. If you want to know what is ridiculous rules is, just look at Masked Hero, how can they call it a fusion monster without merging 2 monsters with Polymerization?