Notably this is, as far as I can tell, just rumor, and not actual product information. But sure, let's go ahead and take it at face value...
First, I think it's great and a net positive for everyone that Pentax would do a nice crop-CMOS camera. MFD is a small sliver of the overall market and everyone in it (Phase, Leaf, Leica, Hassy, Pentax) benifit when more photographers hear about, try, or purchase medium format. The main path to growth for anyone in MFD is to increase the size of the pie by getting another 1% of the total market. As much as the narrative is more fun to enjoy when it's billed as P1 vs Hassy or P1/Leaf/Hassy vs Pentax the truth is the narrative is more [all MFD] vs "good enough".
Second, this is nearly post-for-post the same conversation that takes place
every time a new camera is released in the lower-end pricing range. Go back and read the posts here or any other forum when the 1D, 1Ds2, Mamiya ZD, D3X, 5D2, D800, or Pentax 645D was announced/rumored/shipped. Basically some people say the sky is falling. Yet Phase One has done *better* and better (revenue/profit/product-quality) every year since the financial crises.
Notably to this thread this has included the years for which Pentax had offered a roughly $10k Pentax 645D at 40MP which was more or less the same sensor as in the H4D-40 and similar (at least in spec) to the p40+ and IQ140.
Someone said earlier the only difference would be flash sync and wireless tethering and tech camera compatibility. Here's a continuation of that list in no particular order:
Capture One compatibility (both for tethering and for raw processing where the algorithms have been fine tuned with great effort to get the most out of the camera), tethering experience and speed (not all "usb3" cameras will have the same actual tethering speed, a lot depends on the quality of the usb3 implementation and internal processing speed of the camera), color profiles, quality of the high ISO (specs are meaningless here, if/when hassy and Pentax ship a comparable camera we will have to compare the final resulting images at high ISO. And don't assume because one company has spec'd a higher ISO setting that they are getting better quality at high ISO). Availability in rental houses and rental studios as a main camera or backup to a personally owned camera, familiarity of digital techs and assistants in major and minor markets, quality and speed of professional support/repair in a particular market, quality and variety of made-for-digital lenses, look/feel of camera, burst speed/depth (very very few MF shooters need 3fps, but many want sustained shooting which has no buffer limit and want review of the last image to be immediate even when a long burst is shot), fast focus mask in the back (useful for fashion, but amazingly useful for sheimflug movements, double tap for 100% focus review on a specific area without having to first zoom then second scroll around, customizable highlight warning, variety of grid overlays including user movable guides, metadata entry for at-time-of-capture horizon/pitch for automatic batch correction of perspective and horizon, FireWire 800 in addition to usb3 (nice as a backup and for longer cable lengths including a manufacturer approved 33' cable), extremely high build quality with great history of durability and longevity (we have many h25 users still despite being 11 years old) compatibility with 3rd party cameras like the RZ, Contax, Fuji 680, etc with unique features like waiste level viewfinders and built in movements and dedicated fan bases.
O, and yes, flash sync speed, wireless review/control, and tech/view camera compatibility
.
The point is the sky didn't fall before (quite the opposite actually) and isn't falling now. But we are, as quality-discerning photographers getting more and different options, and that's great news for everyone.