There's a tab Following in the top and it shows people that you follow and their activity. I use it daily and haven't noticed anything of what they describe.
Now, there are other problems obviously: one is how aggressively Twitter was pushing their "recommendations", so for a while the app used to switch back to recommendations without asking for permission, which was really a douchebag move, but you just switch it back to Following tab and timeline again works fine. I haven't noticed this lately, so it could have also been just a bug they've fixed. Another issue is that they mix notifications from "friends of friends" (in Facebook lingo), which also can suck as sometimes ppl you follow happen to follow idiots (¯\_(ツ)_/¯), but you can just block annoying people and after some time trash filters out.
So it's far from perfect, but on the other hand it's not that big drama as some ppl try to present it, honestly. At least for my needs and my circle of online friends and interests...
> One of the main ways I was using Twitter is to find people doing interesting things and then follow them to see what they're up to. This no longer works since you no longer see tweets from the people you follow unless they go viral.