Here's my two pennies. In my opinion, vector art tools do not lend themselves to pixel art production. I've got Grafx2 (It's like stepping back in time!), Aseprite and a really old copy of Photoshop. When pixels rule, vectors struggle. Each one of these programs has its strengths and weaknesses, but I think you need to devote some time to finding a pixel art program that you feel comfortable with. Or hire somebody!
I'm actually experimenting with a pixel art +(PETSCII-like) tile based graphics editor for Adventuron (with layers). For sure the vector style is limited, but it's a really fast and byte efficient way to build a scene. Think of all the iconic "The Hobbit" graphics that were entirely constructed with vectors.
For those of us who grew up with 8-bit text adventures on machines like the Spectrum or Commodore, vector art is a key part of the medium. The slow line & fill systems, a necessity because of the lack of memory on tape-based machines, produced some very rudimentary, but very memorable images.
I could never do anything decent with those systems. Mind you, I also could never do anything decent with pixels! :)