I remember having the same thoughts when I bought my Sailfish and posted the question here. At the bottom is a photo of a tackle storage solution:
viewtopic.php?f=2&t=19834
I ended up concluding that adding storage draws wouldn't provide a whole lot more storage then just using my fridge for storage so that is what I did. I keep my first aid kit, sun screen, WD40 and a mess of other stuff in there. It was a bit rusted so I gave it a "face lift" which is described here:
viewtopic.php?f=2&t=20298
For the microwave, I ended up adding a 1500 Watt inverter to the boat so I can run it at sea and that has been a big hit. I use it to heat water for instant coffee of tea, prepare microwave popcorn, and cook hot dogs. It's great to be able to have a bit of hot food at sea. I've since added a Keurig Mini machine and can now prepare an excellent cup of coffee at sea. The inverter discussion is here:
viewtopic.php?f=2&t=20373&p=128087&hilit=inverter
Back to the storage question - I seen a few solutions that remove the fridge and capture all the potential space under there as there is a fair amount that is currently just wasted space. One just removed the fridge and carpeted the whole area. A similar approach is described here:
viewtopic.php?f=3&t=21511