First of all, I write this post before checking if there's any post by SM to tell us of any changes for the new season. So it won't alter my current perception.
I noticed at first hand the new season is shorter. Back to 14 days, instead of 16 or 17, the length of Season 6.
I reached my goal. The one I set higher toward the end of Season 6 I mean.
I finished Season 6 in Diamond II league, one up from previous season, and it felt a little easier than on last season to reach it. Although the last 2 days were complicated, and the competition fierce, I expected it, unlike the previous season, when I wasn't prepared for the sudden increase in my opponents experience and card levels.
But it was worth it. I've been collecting quite a few reward cards throughout the season. Nothing really spectacular at the end of it, but the sheer number of 50 cards, allowed me to level up some monsters.
But at the end of the last day, I did get a legendary reward card: the Black Dragon. Now 'all' I have to do is level up my dragon summoner so I can use it in battles.