I doubt Schiit would cannabalise the Lyr so soon with a perceived upgrade. Balanced solid state would differentiate the new amp and may be justifiable to those who've just invested in the Lyr. I don't really have a preference at this stage, but I suspect Schiit are too sensible to flood the market.
Who's to say the balanced amp would be nearly as powerful as the Lyr is, or even tuned with the same impedance goals in mind? The Lyr was a purpose built HE-6 and LCD-2 driver that just happens to work with other headphones. The next amp might return to more mainstream needs, instead of the HE-6 nuclear reactor type power demands.