I'm relatively new to using Sigil, but have found it a really useful and reliable application, even if it doesn't have a "make all backgrounds pink" button or the application equivalent of a gold and papaya themed bidet.
(Excellent blog post by the way!)
If it helps a little to keep you sane, motivated and able to continue to devote time to actively maintaining and developing Sigil and keeping it on track, I say go for it, Valloric. A small addition to the Windows installer is a very small price compared to the potential benefits for users.