How to turn wall oven into kitchen storage space?

i do!

That's doable as long as you do have a full stove installed elsewhere. Of course, you'll need someone knowledgeable to safely close off the fuel source(s) as you don't want to take chances with a future gas leak or electrical issue.

But ovens including wall ones are usually pretty deep. You may want to consider using lazy susans on the new shelves. Or plan to store things you rarely need at the back of the new shelves. I have a cabinet with shelves above my wall oven and it is a pain to get to stuff in the back of the shelves :( IMO really deep shelves can be hard to use as open "decorative" storage but maybe that's just me!

Would a large microwave fit in there. Another idea would be to install pull out shelves with stand mixer, toaster, crockpot etc on shelves Put electric plug on back wall. Leave plugged in and pull out shelf when you need to use something. Or you could use same pull out shelf concept and do a coffee bar.

They have built in microwaves but they can be pricy. My large freestanding Amana measures 23 wide x 15 tall x 16 deep(18 deep with handle).

In our last home, the previous owner removed the entire wall oven cabinet. There was already a wall to the right and he had a wall built on the left side and a full louvered door and shelves installed. Instant pantry.

I took ours out and put in 2 shelves. The bottom area is half the space then split the top half in 2. I went to lowes, bought a 4 x 8 piece of playwood and had them cut the shelf sizes I needed. I used metal L shaped brackets with screws to hold shelves in place. Paint shelves before putting in if you want. If you don't want a raw edge, you can get a piece of molding and put along front for a more finished look. I keep the things I use most in the spaces so I have them on hand. The top shelf is for all plastic wrap, foils and boxes of various size bags. (snack, quart, gallon, parchment paper etc.) It's especially good for the long rolls of foil. I always have at least 2 boxes of each. The middle one is for my mixing bowls and such. The big area is where I keep my stock pot and pans I use on a daily basis. This works out great since my new stove is next to it. Everything is pretty much right at hand.