This reminds me of one Christmas-time shopping moment: I turned down the aisle with LEGOs, looking for something for my niece, and there was a lady looking mournfully at the kits on the shelves. I asked if she was okay, and she said her kids loved getting LEGOs as presents but all they ever did was build the kits and sit them on a shelf, which she hated because she wanted to encourage creativity.
I offered the solution I'd used with a cousin: buy a bundle of basic bricks, plus three different kits. Open the packages and dump all the pieces together in one box, and wrap that as a present -- and don't include any instructions! She stared at me for a moment then her eyebrows rose and she laughed, and said that was perfect. I helped her pick out five kits; she had three kids and decided to make them one big shared gift rather than a couple small ones each.
I did the same with presents for my niece: I knew she liked castles, so I bought LEGO castle kits, but I always threw in extra bricks and saved the instruction booklets for later -- in case she asked, though she never did. For every kit I got her, I also got sixty or seventy basic bricks, and she did her own castle designs.