For the OP, I wouldn't worry too much, if nothing else they'll add skills that help enhance the way you already fight. FFXIV combat system has always been more additive than replacement. Does more building on itself.
I would worry more about things getting too complicated (or too simplified) depending on what your class is "too much ____" of at the time. I used to play my PLD a lot more until they added the magic and MP management stuff to the rotation. Not saying it's hard to do, but it was more than what I wanted to do while playing the class - but I haven't been a PLD main for awhile; and I know adding more complexity to the class was on the wishlist for a long time. So kudos for them because I wholly understand that desire as a WHM main. I want a little more complexity for that class.
But the beauty of FFXIV is that switching your main class is almost par for the course in almost every expansion - and sometimes more often. One class changes in a way you don't quite like, but another class becomes your absolute JAM and you rock it like it was always your favorite. My main list since 2.0 has gone:
WHM-> WAR -> MNK -> WHM -> PLD -> SAM -> WHM
I keep goin back to WHM. It's definitely the class I have the biggest relationship with and has solidified itself for me. But Dancer is gonna pose a huge threat so who knows what it will be in the future!
