Defensive options, in a perfect world, should not be preferable to offensive options, and vice versa. I think they tried to make them about equal in Ultimate versus the imbalance between the two in the older titles. Brawl had good airdodges and shields, to the point where advancing upon someone was a detriment as you'd almost always get shieldgrabbed. Melee has bad airdodges and shields, to the point where choosing a defensive option beyond good DI when being comboed will generally get you punished harder than just eating the combo and DIing.
However, due to the nature of the game, people find other ways to be defensive beyond the built-in defense options. Retreating is still almost always preferable to advancing, and even though there is a fast pace, a lot of the time both players are still being defensive in most ways until they're outside of neutral. Raw defense is still almost always preferable to raw offense.
So, the change to airdodges doesn't bother me, since I can basically play how I want and not worry about being shieldgrabbed on every offensive option that I choose. It bothers me more that so many powerful attacks are safe on shield and unpunishable on whiff. You have to wait for an option after they whiff the attack or just eat the shield damage. I find that aspect of the game the most frustrating.