I'll have to update that entry on the wiki for 44.128/16; its definition was originally as a test-only subnet. I don't know that it's used much for that anymore.
Yes, it is widely used here for testing purpose. Even to get around some annoying 'bugs' like the need to assign an IP-address for every Linux AX.25 interface (only used for APRS and no IP). Moreover I often help other system operators by remote and don't want to think about which RFC1918 address space is locally used. I just use 44.128/16 and I'm sure it will not clash in any way with local requirements.
It might be time to return it to general assignment like any other regional subnet.
That might break connectivity. Everybody is aware that 44.128/16 is used for testing. We don't know how many people are using it right know. And we don't know how many people will use it in future since they are used to it but not recognizing the change of purpose.
I don't recommend to change things as long as we don't run out of addresses.
73 de 5H/DG8NGN, Jann