The fact that it's still available in the Community Edition, does not mean that it will not be removed there too. And I'm sure not all developers, can use Community Edition in development, because, not all features are available in Community Edition, and it's very limited by the size of the database and connections (even after increasing). So, for most of the customers, it's rather impossible. But now, InterSystems I would say forcing to use it in development by any developer. So, I see, no reason of pushing Community Edition as an option for developers. It's a good alternative, but useful for a minor part of the developers.

Well, I've asked about it through the ideas portal, and you mentioned some flexibility

It's ObjectScript, so, it has some flexibility. The only issue is login and password, and using OS-based auth, is a good way to solve this, obviously if OS-level is protected enough.

For instance, you can raise issues just by terminating the process with an exit code higher than 0 with $system.Process.Terminate

irisowner@ca22f45b16b1:~/temp$ cat commands.txt 
_SYSTEM
SYS
 write "hello world"
 write "I'm: ", $username
 if $g(condition,1) Do $system.Process.Terminate(,2)
 write "terminated?"
 halt
irisowner@ca22f45b16b1:~/temp$ cat commands.txt | iris session iris; echo Status: $?

Node: ca22f45b16b1, Instance: IRIS 

Username: 
Password: 
USER>
hello world
USER>
I'm: _SYSTEM
USER>
Status: 2

If you call some InterSystems internal interactive tools. So, most such tools have non-interactive endpoints, so, you can call them directly, and no interactivity is needed.

The hardest part of this is a login and password, and I would recommend configuring OS-based Authorization for %Service_Terminal, so, it will not require login and password. Everything else is quite simple if your script is not supposed to answer questions there.  

cat commands.txt | iris session iris > output.log

and, the content of commands.txt, is something like this

write "hello world"
write "I'm: ", $username
halt

Important to finish the script with halt command, and if you still wish to keep login and password, the first two lines should contain login and password

irisowner@ca22f45b16b1:~/temp$ cat commands.txt 
_SYSTEM
SYS
 write "hello world"
 write "I'm: ", $username
 halt
irisowner@ca22f45b16b1:~/temp$ cat commands.txt | iris session iris 

Node: ca22f45b16b1, Instance: IRIS 

Username: 
Password: 
USER>
hello world
USER>
I'm: _SYSTEM
USER>