The Olympus OM-D E-M10 Mark IV isn't much bigger than some compact cameras with much smaller sensors yet it's much more versatile, has a great collection of features and produces better image quality.
Very compact; yet versatile camera; Tilting screen can face forwards for selfies and vlogging; Live Composite and Live Bulb mode make long exposure photography easy
Sub-APS-C format sensor; No weatherproofing