While I agree in the sense that it's interesting they're making it for just one console, the install base of the PS4 is far from small. As is, it's growing quite well monthly with the Xbox One following suite and the Wii U a bit behind that. They'd reach the 150k sales if about 1% or less of PS4 owners bought the game (not sure of the current sales data, but I digress). Still, if you can't expect to make a profit on the best selling console, you really need to prioritise making better selling games.
The Disgaea series has been a favorite for quite a few people and the following is quite fanatical. Still I don't see the series becoming huge on the home consoles. The PSVita on the other hand.. *looks at D3 and D4 Vita versions on my shelf*