Gather ye round for details of the Overwatch [official site] competitive season 2 changes, direct from the maw of Jeff Kaplan. The changes currently include the abolishing of sudden death rounds, a new skill tier system and more:
Too long; didn't maw?
So the prompt to get rid of sudden death rounds to deal with tied results was because players really didn't like the way losing (and possibly winning) felt with those matches. Instead Blizzard will be switching assault, hybrid and payload maps to use a time bank system where how fast you end one round impacts the time you have on the next. The video has the full details of how that works and how it's different from current time bank aspects you'll find in the game. Control maps are sticking with the season 1 method where you win three out of five matches, by the way.
The trade off here is that you'll sometimes get a match which ends in a tie rather than always having a winner, but Kaplan's explanation is that ditching unsatisfying sudden death will be worth the [rare] tied match.
The other big change relates to how players internalise or identify with their skill rating. The previous season's skill rating used a 1-100 system to grade players and players would increase or decrease along that, sometimes by fractions of a point.
Listening to Kaplan it sounds like the 1-100 wasn't representing linear progression, but the normal distribution curve you tend to get in games like this where most people are clumped in the middle and then you get some super-skilled or super-awful outliers at either extreme. Kaplan says that with a skill rank of 60, players tended to respond as if this wasn't a particularly exciting thing, maybe seeing it as a grade D on a school paper when in fact "you were in the top 6% of all Overwatch players".
He also says that people would invest incredibly hard in that single number, getting really upset if it dropped a bit after a bad game/bad few games.
In response Blizzard are switching to a new system. You still get a skill ranking but it's on a scale which deals in thousands and not 1-100 and so you'll go up or down whole numbers. But the important part is that there are new tiers every 500 skill rating so players can identify as a "gold" or "diamond" or "bronze" and have that be more of a reliable/stable competitive identity. There's essentially a bit more wiggle room so that losses don't have as much capacity to affect the skill identity you have.
The tiers are the usual precious metals and mastery nods: bronze, silver, gold, platinum, diamond, master, grand master. For everything below master tier, once you've achieved that tier you never drop below it (i.e. there's a high water mark aspect to tiering). For the high ranks you can drop down as far as diamond if you have a nightmare week/month/season.
You also start to suffer from skill rating decay. After seven days of inactivity players in diamond, master and grand master will lose 50 points per 24 hours. If you take too long a holiday you're at the butt-end of diamond and will need to clamber back. Rewards at the end of the season are based on the highest tier you achieved.
Other topics touched on in the video include that Blizzard are narrowing the difference you're allowed in skill ranking when grouping up with other players, changing the competitive points system and so on.
The changes will be up on the public test realm (PTR) if you want to give them a go, and more exact patch notes will probably arrive when the team has had a chance to process the responses to the changes from said PTR.