Remove the small table in the corner next to the short sofa and the short bookcase behind the long sofa. Try moving the long sofa under the window. Put the short sofa where the long sofa and bookcase were. That should free up more space around your coffee table. See if you like the new arrangement.

To me the partition would be better removed...(without knowing how the guest room is used ) it is obvious it is really hampering the room for daily living...things seem crammed together as you say...and there are open wasted and hard to use spaces that are too small to put to a use....my question under what circumstances and how often do you have guests...and would it be better or possible to give your guests your sleeping space as they may be more comfortable with the privacy?...and space?..then you can combine the sleeping and tv space more for yourself and leave all the open space for entertaining and dining ..a desk even?

As to children play area ..not knowing the fullness of that need either....there are pull out “gates” that fold away when not needed to define a kiddie area..to keep them and their stuff in one place..while still in complete view and easy to interact with them...when not needed they just pull in to the wall until needed again...

If none of this works then maybe a slightly bigger round table that will accept extra chairs as needed when you have more people than usual for dinner