Prebuilt panels would be more useful if they allowed local variables. This would parallel the way macros allow arguments.
Local variables at the panel (and possibly row) levels would allow multiple instantiations of the same prebuilt panel to be used on the same page. Right now these must be provided inline.
This would save many lines of code for me in my current Splunking endeavors. Row-level scope might be nice as well, but panel-level would be enough.
This would help me as well