The TP system is fine the way it is, the way that it's so dynamic is how abilities cost different amounts to use, and on different timers. It allows a strategic, ever-changing mechanism for battle that forces you to constantly think of the best way to make use of your TP.
The auto attack feature, for now, may look very bland, but it allows for things such as haste, tp gain based on delay, coming from ffxi store tp, and dps of weapons based on dmg/delay. In the future I'm sure that they will add things that have a greater influence on auto attack. We still have normal attacks that are on timers, I know I use all 3 on my lancer, in case people forgot about heavy thrust, pierce and full thrust, as well as the other classes' counterparts.