There has been many critical bug fixed over the last few patches and most of them have been addressed well ones that have been reported to the development team anyways.
If your experiencing a bug please report it on the forum or on discord.
Development has slowed a little due to having to update the web site(s) to meet the upcoming legislation that the Europe has started to roll out for data protection, so while they are doing that it makes sense to upgrade/date some other parts of the sites that need it (no point in doing half a job, there not known for doing half a job

).
So, that one reason development has slowed a little.
Another is because well people have time off to be with family during the Christmas period as expected.
They have done lots of work behind the scenes to get the websites and licensing system more update and more secure, not our version of skyline is mostly stable with the odd bug cropping up now and then they have split into different branches free, pro and studiopro (I think that it)... and making them be the way they are supposed to be.
As I understand it.
Skyline Gen 2 will be on the asset store soon and development will continue whilst the preparations to go full v1.0 release to get more features in (like the vegetation billboard system)and more bugs tested and corrected.
Even when released development will not slow down as there will be more features and that added like DLC etc..
Personally I think they are doing a great job and Skyline is very close to getting there just some of the features to port in from gen 1 and it will be a go. Not only that I can not wait to see the new documentation that will teach workflows and stop the repeated questions as you can refer to the doc's and video tutorials.
Talking about video tutorials Tattie has made them and is waiting for v1.0 release so he does not have to redo them every time there is a change in workflow etc, the new documentation site has had a face lift and looks miles more what its supposed to look like and just requires populating at the moment, all sites are now encripted with SSL, there has been loads done.