Nevertheless I took the challenge and use the space-work-around to achieve item key uniqueness and take on the burden of manually updating every single LLD prototype and rule of every single host due to
ZBXNEXT-1190 and ZBXNEXT-1451.
However there is another hurdle to overcome. Network errors on one host interface may interfere operation of other host interfaces of same type.
I've got a 3rd party application Zorka in place that makes use Zabbix agent protocol. Thus there is an additional Zabbix agent host interface dedicated to Zorka on the corresponding hosts.
Whenever Zorka agent is not reachable (eg. application server stopped), it may lead to stop Zabbix agent related checks as well.
This makes using multiple host interfaces of same type finally unusable at all.
Would be nice to get this fixed - and the other mentioned shortcomings of course too