Is it a commitment? I'd d say no. A quick change and some regearing and suddenly a fire age is a frost Mage.
Should it be? I would say yes. A paladin trained in healing magics shouldn't be able to quickly jump into a tanking spec. A Druid who learned to fight as a bear shouldn't easily switch to being a cat. Your specialization should be a meaningful choice, not something you easily switch out of. You trained as a combat rogue? You are not going on be the best at poisons. Trained as a frost death knight? You shouldn't be a very skilled unholy DK. I wish your choice was more meaningful, and changing specs meant a significant quest line to learn your new specialization.