Depends on how many, and which games become exclusive for it. (hopefully not many, I really don't want to buy the same console twice)
Right now, Xenoblade is not worth it on it's own. I'd buy Xenoblade in a heartbeat if it worked in the old models, mostly because I didn't have an actual chance of buying so I ended up just pirating it and I'd like to make up for it. But it's not enough to want to buy another system entirely.
Either way, I'm not looking forward to seeing more exclusives. It's only been three years since the release of the 3DS and it's already obsolete, I really don't want to give this thing any kind of support, and to be perfectly honest, I hope it doesn't sell well.