I really like that as a starter - has my favorite bits from your old templates, and the GFW template.
The only thing is, for consistency, people would have to re-cover every new purchase if we go for a custom design as standard - perhaps not everyone is as anal about consistency as most of us - hahaha
in terms of your question about size - yes for me, size is important (hehe) i am planning to make myself a master template with the spine equally sized across all formats.