Feel free to send detailed feedback on what issues you are facing at the moment to my support email on the site!
As you may expect, running a site that aggregates various AIS feeds from both terrestrial and satellite can get quite pricey so I have had to scale back on certain data sources, this included the ships previous tracks, future tracks and also certain characteristics about the ships journey. Each of those are individual API calls that used to regularly run.
I chose to redevelop the UI to be more accessible for a wider community, the old UI was very unusable with screen readers and also was a bodge of multiple UI frameworks which regularly broke in recent browser engine updates, especially on Safari which is our largest source of users. The new UI is designed from the ground up to be even more efficient on page loads and server hosting (for example, as of it being deployed we have had around 70k unique page loads of which only 2GB of data has been served in that entire time frame - around 28.57 kilobytes per session). The previous site was on the order of triple that value.
As I previously said, I am more than happy to do whatever changes to the UI to suit the users better - one thing I am working on at the moment is the ability to mark a ships "confirmed-ness" on the map in cases where we do not know if it is a tesla carrier ship.
Unfortunately, if it's an issue regarding the detail of the data - I'm afraid we are out of options at the moment while I try to find some accurate AIS sources, I may be able to re-gain some of the detail but only for ships in range of terrestrial receivers (mostly tends to be once the ships are in Europe and maybe around some key ports if we are lucky).
Now, I totally agree with what you're saying. My only issue with the new UI is related to the map itself. It was much easier to read, and the names of cities and countries were in the international format. Regarding the ETAs calculated based on speed, I agree that they were more misleading, and I would have preferred it to only show the arrival times mentioned in the ship's itinerary.