While the new table function in Impress is commendable, it is not consistent
with the general "quick editing" option for object editing:
I much prefer to have it unchecked, i.e. when you click on an object with text,
the object is selected but the text editor is not active. You have to double
click to do text editing.
I find this much better because otherwise all non-text editing of these objects
becomes awkward and difficult to perform.
Unfortunately the new table objects do not follow this setting and are always
opened for text editing at the first click, regardless of the "quick editing"
setting.
Apart from the logical inconsistency of this, forcing you to change mindset when
you switch from editing another object to work on a table, I found really
difficult to apply some operations to tables. 
In some cases you first click on it then have to press Esc (in this way is seems
to exit text editing mode, though the object border inconsistently stays the same). 
If you want to access the contetx menu per the table object (NOT the text
editing context menu) you have to aim with the right-click precisely at the
outer edge of the dotted border, which is far from easy if you want to be fast.
To summarize, the editing behaviour of the table object should follow the
conventions set by the "allow quick editing" option.