At a glance, the string templating system they were trying out looked pretty good to me.

And clearly a lot of work and time went into it with the previews.

The fact that they pulled it back suggests they looked down deep into an abyss that looked back at them, and what they saw scared them.

I don't know if there has been a published deep dive post mortem on the whole string templating thing, but I am quite comfortable with the team yanking it out if they felt it wasn't right.

Honestly, I still write a lot of perl, and while interpolation is nice and good to have for simple things, I find myself using sprintf more and more in production code, especially in the cases the examples always show off, such as needing to alter the variable, add two together, etc. I assume those are just shown to illustrate you you can do that, and not imply you should, because commonly using arbitrary code execution within interpolation is something I'd feel compelled to beat out of my coworkers if I encountered it regularly.

Interesting point - syntax sugar was nice when writing code by hand. Now we'd be fine if no such sugar was added anymore ever again.