For every complain like that in Go I'll find a hundred in C++, ten in Java / JavaScript / Python.
As to your question, as a full-time Go programmer: this doesn't come up often.
When it does, I google "slice tricks" and copy & paste the formula.
It'll be fixed by next release because generics will enable writing a function that does that and that function will be in standard library.
Why wasn't this fixed before generics? Because the only way to do it would be via a compiler built-in function and Go team is rightfully reluctant to bloat the language / compiler for minor functionality like that.
