I don't think Marvel ever set out to create second rate characters deliberately. It may have been the end result, but they were trying to do fresh things. Captain Marvel was a place holder for the copyright to the name, so that much is true - but I don't think they had reduced expectations - they were probably trying to ask other artists to help with ideas so Kirby wouldn't have such artistic control of the franchise. But I guess that came up empty.

Green Lantern obviously has something to do with early Captain Marvel, and Nova later. Gil Kane of Green Lantern fame redesigned the costume - I think - and it owes a lot more to Green Lantern stylistically than the original. But at the same time they made it more like DC's Captain Marvel...

On the matter of Colletta inks - Tom Palmer and Dick Giordano - two acclaimed Colan inkers - are from the same school of inking Colletta graduated from. I don't find his work much different with the exception of some zip-a-tone from time to time.