I don't think 3rd parties care who's console is leading. It's more a matter if they understand the market for that console and if their existing IPs will work for the console's market.
The problem with Wii is it went in a different direction than any console previous. The market was strange to 3rd parties and the core on Wii always complained about 'waggle' and 'imprecise controls', critics especially, causing Wii 'core' games to underperform and so 3rd parties stuck to what they knew.
Now if N6 is another complete innovation like DS or Wii, or further goes into the blue ocean, I think 3rd parties will sit by and see how Nintendo fares and then copycat on what seems to work just like this gen.
If N6 has core appeal, of course they'll jump on board with their current IPs and strategies and leave the expanded market mostly to Nintendo to swim around in.
