We already use the seating planner in Class Charts which pulls through information such as which pupils frequently get red marks when seated next to each other, (based on the inbuilt green/red points system), and integrates with SIMS so that rich data such as ALN status, health issues, whether the child is on report etc. can be seen at the click of a button.
You can create your classroom layout pretty exactly, including different shaped and sized tables from rectangles to hexagons.
You can also move individuals or reseat a whole class according to various parameters with a couple of clicks, have multiple seating plans for different activities, can easily print them out for supply teachers with photos if needed.
I also use iDoceo for planning which has seating planner functionality.
What might your software do in addition to this?