D600 for first DSLR

Do you guys think its worth buying D600 as first DSLR ?  I have owned used mirror less /interchangeable lens cameras for last 3 years.  I just think I take good photos, and if not , my wife takes amazing photos, I wish I could buy her a good  camera for best times in our life (we just started living together).

1. Maintenance cost ?

Apart from lenses does it cost to maintain a DSLR , I hear a lot about sensor cleaning, etc ? Would it be required a lot ?  Not to mention, each photo is now 20 MB, I better start getting storage also .

2. Learning curve ?

Does it take a lot to learn using features and getting best out of D600 ? I understand basics of photography, how aperture, shutter speed, ISO affect the picture.

3. More lenses ?

If  I start with kit lenses 24-85mm VR Lens, 70-300mm VR Lens, will it cover most of things I need to shoot ? , people (family functions) , kids and places.

4. Shelf Life ?

Point and shoots are in people mobile phones , will it soon happen that we would see people using Full Frame camera's  like Point and Shoots ? If so , will it happen in next 5 years ?

5. D7000 ?

I have seen reviews that D600 is 20% better images than D7000 ,  and can do low light and better video, Is it worth spending that $1000 for D600 compared to D7000 ?

6. D7100 ?

Would it be worth a wait for D7100 ,  has latest features as D5200 and with a weather proof body ?