Well, you lost a bit rewards from getting 2 stars, but I wouldn't say it's too bad... let's say 1 weekly chest more than makes up for all the 2/1 star fails you could possible make - and I wouldn't believe you never 3 star'd.
So at the very worst - you will just need to wait 1 more week and you are back on track.
I find injury more of a reason of my 2 staring than nerfs to heroes.(partly due to nerfs of course, because it further limited good heroes) I mean the commander is still great as it was and it's most important character - karina. Captain is not as good now, but still decent - Nari. You can still spawn the heavy tank with lieutnant.. very good. The biggest nerf is the latest one - sergeant now doesn't drop the tank.. but tbh artillery drop isn't that bad as well! And if artillery isn't your thing you could always take cassandra for that 5% extra def...
I also found the 59 rather hard, it's one of my 2 remaining 2 stars under 60.. 60 won't be as hard to complete, since it will give you more time to build up.