I've been reading the book DESIGNING GREAT BEERS and it has an extensive chapter on hop chemistry. I certainly don't even have an academic mastery of the subject, let alone a practical one, but I'll try to provide some superficial highlights as I understand them.
Bittering, i.e. IBUs / AA%, is primarily a function of the 'soft resins' of the hops, making up to 15% by weight of the hops.
Flavor and aroma are function of the 'essential oils', which make up between 0.5 and 3% of the hops.
There are 3 main essential oils, each of which imparts different flavors/aromas.
The overall effect of a given type of hops is then a function of AA% (of course), the ratio of total oils to resins, and the ratio of the 3 types of oils to each other. The book provides charts of these ratios for many varieties of hops.
Centennial is nearly 2x as 'oily' as Cascade, but the ratio of the 3 oils is quite similar.
What this means in terms of taste or smoothness comparisons between the two, I have no f'ing idea.
Hope this helps