I wouldn't change my kitchen layout strategy just to steam a fish in the micro. Do what you were planning to do, you can probably still steam a fish in a 15" microwave.

Besides, after you try it once you may not want to make it too many more times anyway. Personal opinion only but steamed microwave fish doesn't really sound like the most appetizing dish ever. Just sayin'. :-)

But a speed oven might be just the ticket!

We are putting in an OTR speedoven in an upper cabinet. Can't tell you how I like it yet but it's an idea.

We bought an inexpensive, small (14.5" deep) m/w and put it on a shelf in a beverage area along with cook books and decorative stuff. If I could find a smaller one, I'd replace it. So far I've only used it to heat milk. My induction cook top is easier for melting butter and my new ovens are better for all the other tasks.

We hid a pair of microwaves in a walk in pantry/storage room. We have two because, while we don't use them often, when we do we do multiple plates. Usually rehearing two plates of leftovers at a time. We hid them because we're not a big fan and didn't want to waste space or buy expensive wall mount or drawer ones.

You may want to checkout MW cooking cookbooks. There are thousands recipes of delicious dishes. Some dishes turn out much better than preparing in conventional way.

Cooking with MW is healthier (requires less grease), it generates less heat and dirty dishes since you can cook and serve in the same plates/cookware.

We use MW oven every day. We love to cook, to try recipes from different regions, countries and cultures. We pair MW with regular stove, oven, BBQ station and other appliances.

In our upcoming remodeling, we plan to have a multi- purpose MW with oven capability, since at times we would like to have more than one oven. We will definately use MW oven and BBQ station while our kitchen is being worked.

you could always steam the fish in your dishwasher.