Going to chime in.
I think you are asking very different questions and the answer for you depends on what you shoot and the reasons you shoot (i.e. hobby shooting or shooting for your income). You mentioned "effects" which makes me think you are shooting in JPEG rather than RAW.
I currently shoot with a Leica rangefinder most of the time because I desire a small package that is easy to carry around. Fits my shooting style. I've also really begun to appreciate manual focus making use of depth-of-field markings on the lens.
I recently bought a D3200 for my wife for an upcoming trip to Italy. Wanted something that is compact but can produce decent images if used correctly. Also bought this for my niece who is just starting out in photography but has a good eye.
I was pleasantly surprised by the D3200. In the past, the FX vs DX debate was largely centered on the technological restraints of sensors available at the time. DX sensors were much worse than FX sensors in low-light. I'm not sure this is currently an issue.
FX sensors can be better if you routinely shoot wide. DX sensors have some advantages if you routinely shoot long.
Obviously this is heavily dependent on what lenses you own.
Playing around with the D3200 with some of my lenses surprised me in a good way. I took this moon shot last night with a D3200, 300mm prime, and 2xTC. This is combining both elements of your question
The D3200 is a consumer body. It requires more work (hunting through menus) to make adjustments compared to my D800.
If the "convenience" factor of easy access to controls matters for your workflow, the D3200 may not work for you. If you need the more advanced auto-focus of the D800, the D3200 may not work for you. If you intend this to be a backup body and you routinely shoot wide the D3200 may not work for you (depending on your lenses).
Importantly, realize that many lenses won't work with a teleconverter. These same lenses may be usable on a DX body. Depending on what you have, this may really be the most important factor.
Again, complicated question that doesn't have an easy answer. It depends on your lenses. It depends on your shooting style and workflow. It depends on why you "need" a D800 body in the first place.