Hi Kean,
Interesting point, have you done any sims that support this?
I look at this as a real boon for output stage devices, where efficient heat transfer is critical. Considering a typical (non CFP) output stage the backplate (collector) is (usually) at rail potential and the heatsink at ground, the capacitance will actually aid in decoupling and bypass, so a good thing and no effect on stability.
Another large benefit is the ease of assembly after the devices are coated and cured, especially using my YYZ heatsink compound ($5 paraffin / silicone stick lubricant).
BTW, here's the test subject - an MJW21196 that has been single dipped in undiluted waterbased polyurethane and has now cured for 5 days.
