Depends on what you shoot ... and the size of your final print ...
What I shoot, which is general photography, a little bit of this and a little bit of that, (sports, theatre, Street, family, flowers), 99% of which is in available light ... sensor size does not make a difference.
In the beginning of dSLR photography, the IQ of FF versus APS-C at 8x10 was truly significant. APS-C at ISO 1600 was barely acceptable, (a bit worse actually than shooting Tri-X pushed to 1600). When I upgraded from a 20D to a 5D ... the difference was like night and day in low light. Ultimately I move on to 1Ds which had the IQ and build quality I desied and needed, (I'm hard on my cameras.)
For fun I tried out MFT. The smaller sensor delivered very digital-ish looking images to my eye, but non-photographers didn't see a difference. The Olympus IBIS is wonderful and went a long way in compensating for low light IQ of small sensors.
Now I shoot with Fuji. The mirrorless APS-C is a nice compromise between the small footprint of MFT and the IQ of FF. The Fuji image, to my eye, looks film-esque with the Oly and Panasonic MFT images looking digital and the Canon files looking somewhere in between. But these visual differences are subtle and to the average viewer, insignificant. I shoot Fuji because the high quality build of their equipment and equally important, Fuji lenses are all exceptional.
Being a former professional, I tend to buy pro level equipment and I have little to no experience with lesser grade cameras. As a former pro, I think my desires and expectations of my photography are/maybe different than the expectations from most non-professional photographers.
There is no perfect general use camera. There is no perfect general use sensor format. I personally feel that, for what I shoot and how I shoot, the difference in IQ between FF and APS-C is insignificant. Until recently, Nikon hadn't a high level APS-C camera and most/all of their APS-C lenses are inferior to their FF lenses. If you go Nikon APS-C, I think you should give serious thought of all FF lenses.
For new photographers, the grass is always greener ... especially a desire for FF. Having shot FF, I recognize that FF has no magic. FF will not make you a better photographer, but it may make some photographs better.
If you have resigned or thinking of resigning to expensive FF lenses ... then you might as well go FF. Cameras, unlike lenses, are somewhat disposable. After a few years, usually cameras will have improved enough to warrant an upgrade ... but a good lens is forever (or pretty damn close to forever).