Hide a formula bar when a formula or text is above a certain ceiling
The problem is, more than just formulas, if you have a lot of text in the cell, that that can also block out the entire sheet. Even if you could dock the formula bar elsewhere, it would still protrude onto your sheet's work area so that would not give you much of an advantage.
You probably know you can go to Tools > Options > View tab, and deselect Formula bar in the Show section. If you record a macro to do it, you'd see this code line:
Application.DisplayFormulaBar = False
To automatically hide the formula bar when either a cell's formula length or text length is greater than, say, 50, try this:
Right click on your sheet tab, left click on View Code, and paste the following procedure into the large white area that is the worksheet module. Press Alt+Q to return to the worksheet. Modify for character ceiling if 50 is too many or not enough.
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Cells.Count > 1 Then Exit Sub
On Error Resume Next
If Len(Target.Text) > 50 Or Len(Target.Formula) > 50 Then
Application.DisplayFormulaBar = False
Else
Application.DisplayFormulaBar = True
End If
End Sub