FF14 will be significantly different from FF11, but if you didnt like the basic concept of 11, you probably wont like 14. 14 will be bringing some better improvements like making it easier to solo, allowing you to sell things while you are offline, improved combat, etc. However, it is a real MMO, it isnt wow. WoW has become the mainstream, but wow is so watered down its amazing. It will take you roughly a year of 2-3 hours a day to max out a class in 14. It takes a lot of effort to level, to craft, to battle. Things take time, and you need to do what you are doing....however, it's that same concept that gives FF11/14 a great community and square puts a lot of time into making gameplay at all levels worthwhile.
If you only have time to play 10-20hours a week, it will take you a long time to get things done but its a superior product imo. Plus even if you dont have much time to play, doesnt mean you wont enjoy it. FF14 looks great.