Besides the usual problems of these one-FET + traffo schemes, this plan doesn't seem to have any additional ones to me.
The question is: what's the point of eliminating such an uncontroversial component (the coupling cap)? If you want the sound of the classics, why try to re-invent them?
For completeness I think those problems are high distortion mainly, I guess. Distortion stems from:
- Amplifier non-linearity. This could be significantly reduced by eg. adopting a unity gain non-inverting topology. The modest gain obtained by the inverting configuration is hardly worth the excess distortion. This could then be improved again by adding an output stage of some kind to relieve the FET of cable driving duties.
- Excessive capsule loading. A nice simplified model of a capacitor mic consists of a so-called 'active capacitance', which changes dynamically with the sound pressure and 'passive capacitance' which does not. Loading the capsule with extra dead weight 'passive' capacitance not only attenuates the signal but causes the production of additional harmonic distortion. The Miller effect causes the input capacitance of the FET to be substantial in the inverting (common source) configuration. To make matters worse this capacitance is non-linear producing distortion products of its very own by interacting with the (I'm assuming the two non-linearities don't serendipitously cancel each other, but I haven't checked that possibility). FET input capacitance can be all but eliminated by bootstrapping the drain terminal, increasing input level and reducing distortion dramatically.
Btw... For lower noise, using > 1 GOhm is just about the only game in town once you find a reasonable FET.
Best of luck!!
Edit:
A quick spice sim confirms that noise shouldn't be a problem with this plan. I'd presume that the p-channel noise model is pessimistic, but still noise is dominated by the resistor. Note that your plan reduces noise by almost 3 dB by eliminating one of the 1 GOhm resistors. You could achieve the same result (noise-wise) by doubling the two resistors in the original plan.