It would be nice to have the option for a single filter input that searches all columns on the Grid.  I was able to implement my own custom solution but having to apply that to every grid in my app is cumbersome.

I understand the importance for the flexibility side of having each column with its own filter box, but for simpler apps this is overkill and a single filter box is enough.  The column component already has the [filterable] flag so this can possibly be used to exclude any columns if necessary.

I was thinking of something similar to what is an out of the box feature for the Datatables JS plugin

https://datatables.net/

Default search box that searches everything.  Very simple to use and understand for basic users or when your application only calls for something that simplistic.