Constraints can lead people to be more innovative and creative. That does not mean they universally do, only that they can. Removing such constraints is thus not an obvious improvement with zero potential downside.
I don't use twitter, so either way it doesn't matter much to me. But was twitter not created with this constraint due to the original intention that tweets could be posted by sms and were thus constrained by the format of sms itself and not actually an inherent and necessary part of the platform?
It seems like there's room for twitter to provide at least a method for long form content.
Maybe have it seperate from the actual twitter feed and let people use a normal size tweet to link to it?
People already seem to use it for longform content, providing a way for people to do it efficiently may provide a positive change. It would give people a reason to use twitter who otherwise might not because of the content limitations.
Even adding such a system, I imagine the bulk of tweets will still be the 280 character kind, but it would provide a built in method for that occasional time you want to write something longer.
Any transcript of an in person conversation would substantially dwarf all but the longest comments; even a minute of a typical podcast is enough to fill several pages worth of paragraphs.
That we all seek the simplest way to express a thought is not a bug, it is a feature. Audible speaking has tons of filler words and useless offshoots that do nothing to further the main concept being conveyed. We choose to write down sentences instead to minimize cruft and maximize content. Twitter just takes it a step further, and incentivizes the optimization of written text itself.
I think twitter tends to be good for sharing relatively uncontroversial information, making jokes, quick "shower thought" type things, but really bad for anything that requires a deep conversation with someone else.