A bit weak in the corners at 24mm it seems ...
Sure, on the 5Ds R. Subjectively the 16-35mm III seems to be better at 24mm.
Whatever weaknesses it might have I expect this lens to be a commercial success because it covers a much needed range.
In the past Canon 17-85 has had its days even for a short period.
24-105 has for a long time been a best seller so why this one won't?
Nobody is expecting it to rival primes, it offers decent quality an extremely useful range, excellent build quality, everything to make it a best seller.
Hmmmh, the 5Ds R is eating this one for lunch ...