Just do your Overwatch placement matches already
Season eight for Overwatch's ranked, competitive ladder opened on Dec. 31 with a few new adjustments, but nothing major.
Skill rating in Overwatch will be slightly different—players will likely notice they're being matched with players that match their SR. Likewise, higher tiered players (those in diamond and above) will no longer earn SR based on their personal play, only on team play.
Either way, you don't have to be scared to do your Overwatch placement matches. Some players put off their placement matches, afraid of where they'll land among their peers. Players don't want to be ranked lower than their ending rank for season seven. Chances are, however, that players haven't changed in skill since the end of last season. Overwatch's off-season for Competitive Play is only days long, which means there isn't much time to improve or regress.
Don't worry about placing lower, anyway. In fact, Blizzard used to place players lower than their ending rank to give them the feeling of improvement over the next season. Many found the practice demoralizing, though—and Blizzard stopped doing it in season six.
And that means that you're likely to be placed very closely to where you landed last season. Of course, your placement matches are likely taken into consideration, but it's more than likely you'll land right around the same as last season and continue to progress from there. (Blizzard has not been completely transparent about the placement match system, so it's not clear how they exactly factor into tier placement.)
Don't be scared of your placement matches. Your SR is just a number—and the real fun comes in improvement throughout the season.