As i like to say, the only reason TP existed in the first place was because it was in 1.0. It was one of the staples of 1.0 so they kept it, but they never really realised WHY it was a staple- the reason it was such a big part of 1.0 was because it needed to be BUILT UP to use more powerful weaponskills. Having it maxed out completely contradicted the reason for its existence.
However, they soon realised how unnecessary it is, and especially thanks to the job gauges giving most classes something else to have to manage. The job gauges took the place that TP was meant to have, and slightly more along the lines of 1.0's style of resource management, especially looking towards certain classes. Like White Mage. Its bar builds up and that's the only way you can use certain skills. Not many are locked behind it, but... still.