Anything to add ?
It all depends on your style of photography.
I would have the 100-400 f4.5/5.6 IS instead of the 70-300, as I like photographing butterflies, dragonflies and birds and the 100-400 is very adept at that with that extra 100mm.
So my list of lenses reads:
Canon 15-85 IS
Canon 100-400 IS L
Canon 100 IS L Macro
Plus the Canon 500 f4 IS L with a Canon 1.4x Mk.II converter for that extra reach to get the birds. Which is one of my main interests, so not suggesting you should get one
So all in all very similar really.
Have you got or thought about some sort of flash diffuser? Very useful in getting rid of that 'shot with flash' look. I recently got a Gary Fong Light Sphere, I found one on eBay. Excellent device would recommend getting one and an OC-E3 off camera flash cord. Canon make them and they cost a bit or you can get them from Yongnuo, which look 99.5% the same as a Canon one. I got one again off eBay, I always look there first to see if anyone is selling what I want, it came sort of free with a Canon OC-E3 I bought. So I have the Canon OC-E3 which is quite short but OK for most things and a much longer Yongnuo one.
With regards white L lenses you can get things like a Lenscoat, or rain guard, which will 'disguise' them some. But I have not found having a 'white' lens a problem the 500 mm gets comments just because of its physical size.