I've only seen twitter through tweetdeck for the last decade, and I believe it hasn't seen a new feature or design (both in functionality and form) change in at least 4 years ? It has become bug riddled (but I still use it), but all timelines are still linear.
(example: polls have never been ported to tweetdeck)
I don't think tweetdeck has seen active maintenance in years.
I'd consider that a good thing. I avoid updating apps as long as possible because they inevitably add features that degrade the experience (ads, etc).
Prior to the Tweetdeck URL, I used the OSX client which I also really liked, mostly for the ability to just copy and paste an image straight into a tweet. So functionality wise, I feel like my experience has actually declined since then.