That sounds like a very good set up to me.
I like the 4300 solution vs the dedicated pre-pro because The pre-pro will become obsolete sooner than any of the other components. I guess something like 7 to 10 years is typical life of a pre-pro (or AVR). Accordingly, I'd rather spend big bucks on better speakers and high quality amps (for durability) that will (can) stay with me for decades rather than something I will be getting rid of in a few years.
Every year or two the manufacturers release a new model with the latest and greatest features. They have hired smart people to try and convince you that these new features are critical to your enjoyment of your system. Yet lot's of people enjoyed the system they had 30 years ago (assuming high quality).
If you have the big bucks available for a top level pre-pro without it impacting your budget for the other gear, etc. Go for it!!! You'll have my heartfelt thanks, because those buyers are essentially subsidizing some of the cost required for R&D and manufacturing experience required to introduce new technology into lower tier products at bargain prices (like the 4300)!
By the way, the 4300 has an Eco mode which in addition to saving power, lowers the AVR temperature by about 10 degrees. I have never been able to hear any difference at all, but would be a little reluctant to activate it if I was using it for the mains... just in case! However, with my mains on an external amp, I don't hesitate to use Eco mode with the surrounds. The reading I have done on it makes clear that it can not effect the pre-pro section, only the amp section (and I have read nothing to indicate it has audible impact, but until I see testing to verify no audible impact, I am wary).