Well, not quite actually. The main difference between organ on one side and synthesisers and arrangers on the other side is that synths and arrangers have touch sensitive keys, sometimes even after touch. So I would say that synths and arrangers are more likely to have the same type of keybed than regular organs.
That said, obviously higher-end instruments will have better keybed than lower-end ones.
In the past, Yamaha was well-known to have better-built instruments even in the lower range of keyboards, as opposed for instance to Casio. Unfortunately, lately, I got the impression that Yamaha has been trying to cut costs down on its lower-end instruments, not on features because chips are cheap nowadays, but on keybed and general build quality.
Just my 2 cents,
Regards,
Vinciane