Rear intake coolant bypass

The only possible problem I see are:

• it completely bypasses the heads during warmup.
  
• And then it bypasses some coolant flow past the heads when the t'stat is open.
  
• Too much bypass flow in that path will lower coolant pressure in the heads, allowing easier boiling in the heads.

The normal bypass just bypasses the radiator, not any part of the engine. So this is potentially an issue with creating hotter spots in the heads.....