any ideas for house improving?

The more objects you have in a build that Sims can use the laggier your game will get.
My sugestion is to make less but bigger guest rooms. That will remove quite some beds. You won't have that many Sims at the same time on the lot anyway.
Also the raised beds in the last two pictures wont be usable that way, so you can delete those as well.

In the dining rooms you could put the tables further away from each other. Leaving more room to walk around.

That aside, it's really a gorgous house