Lens size is truly where rangefinders show their superiority over mirrorless.
Hum!
A major advantage of mirrorless is the ability to use very compact, high quality lenses like older Leica or Canon or newer one like Voigtlander. No conflict there.
The trade off is no auto-focus etc. This is the very reason why I own a Sony Nex-7 which has proven far more flexible than my Canon 7.