You are not forced to open locks.
No, you are not.
However, if you can blast the door off its damn hinges, why the heck would you bother opening the lock? I mean come on, even if open spells are removed, why wouldn't mages blast locks out of the door or chest?
Same question goes for freezing the lock/hinges of a chest and then shattering it into so many component parts.
Likewise it hardly makes the skill redundant. If you think about how it appeared to be implemented when I ran into it today (cast destruction spell at door, door opens) you could do or think of a number of things to reduce redundancy.
Besides that, lockpicking perks are already redundant because of the mechanic. I've never taken one on my thief.
Or a companion, but yes.
No, but why waste valuable points on lockpicking perks when you can do the job by simply casting one spell? We need to have a more useful lockpicking tree, not less.
You seriously think it is a better alternative to muck around with a companion?
It's a very good question.
You can make the unlock script harder to obtain on doors - expert level destruction spells with expert level mage on an expert level door, for example.
Not so many locked chests without keys?