If there is a secret key stroke that lets me make an Appoggiatura, somebody please tell me, I cannot find it anywhere.

Steve,

In Document options/Grace notes, there's an option for flagged grace notes to be slashed or not, it's your choice.

Is this what you're looking for?

So by unchecking "Always Slash Flagged Grace Notes" it gives us the same option as before to apply the slash as a grace note or leave it off making it an appoggiatura, as it was before?  The term appoggiatura did not show up in my search in the online manual or the knowledgeabase.

Grace note and appoggiatura are two different things and effects playback.

I believe that this document option affects all grace notes in a file. They either have a slash or not.

If you're trying to tell MM what to do, best to use the Submit a request link at the top of the page. This is normally users talking to other users. 

On the subject of Mr Cramer, has anyone ever sampled that Steinway A in the old RCA Studio B? I'd buy a sample library from that piano in a heartbeat. I got to play it a little in 2010.

You can have both slashed and not slashed flagged grace notes :

1) in Document Options -> uncheck the box "Always Slash Flagged Grace Notes".

All the grace notes display without a slash.

2) Select a grace note that you want to have slashed.

Plug-ins : Notes... -> Slash Flagged Grace Notes

Note that the other way around (box checked, Plug-in : Slash Flagged Grace Notes Remove) doesn't  work.

So that everyone is ising the same definitions, Floyd Cramer may have called what he was doing appoggiatura but he was actually describing acciaccatura. This definition is as I learned it 50 years ago:

As nouns the difference between appoggiatura and acciaccatura

 is that appoggiatura is a type of musical ornament, falling on the beat, which often creates a suspension and subtracts for itself half the time value of the principal note which follows while acciaccatura is (music) a short grace note (theoretically taking no time at all), occurring on the beat occupied by the main note to which it is prefixed, one scale-step higher or lower than that main note (sometimes equivalent, therefore, to a short appoggiatura , but in baroque music interpreted differently and more strictly) written as a note lighter in appearance, typically a quaver (eighth note), with an oblique stroke through the stem.

Finale can do all three, of course, but calls all such notation Grace Notes. You determine the values of the notes and whether they come before or on the beat.

https://usermanuals.finalemusic.com/FinaleMac/Content/Finale/Grace_notes.htm?Highlight=grace%20notes 

If you don't like the traditional applications, define them as you will but please include performers' notes so that we know how you want them. Otherwise, experienced performers will interpret them it the performance practices of period in which they were composed.