Contents of the OP copied from gaf as I do agree with that OP and being properly credited.
Summary:
1. Gets into a pissing match with Rare
--How he got into an ego conflict with Rare over Donkey Kong, staled Dinosaur Planet development and more.
2. Cancels Star Fox 2, then steals its code and assets for other games
--Canned SF2 and used its code for SF64 without attribution or royalties to Argonaut.
3. Steals the concept of Super Mario 64
--Argonaut were developing a Yoshi game, they got let go and they used the code for Croc, to be the first 3D platformer, and Miyamoto harnessed their ideas and SF2/Yoshi code and got to market first, then said "too bad" to Argonaut and denied them royalties.
4. Bankrupts the developers of GTA 3
--Body Harvest was being developed by DMA Design, but Miyamoto created a lot of hurdles for the development, causing many delays. Eventually this lead to them going bankrupt, and being acquired by Take Two and merged into Rockstar. These are the people who created GTA 1-2, and their remnants developed GTA3.
Source Video: https://youtu.be/v9GpCCZ6NAE
Source: http://m.neogaf.com/showthread.php?t=1328992
After watching the video Miyamotto looks less like a legend and more like a thug.