See? This is why WOW's talents system is so great. Because it gives you the option of doing what YOU want. Play the way YOU want. SE tried to do something similar with Jobs as they become a specialization but you can still stay on a regular class and mismatch abilities but it is not as advanced as WOW's talent system.
WOW's version of a Dragoon would go something like this...
1st tree would be pet focused.... you can summon a Wyvern to fight by your side and you get passive and active abilities that enhance your pet's power.
2nd tree would be a lancer build where you have no pet but have very powerful attacks and jumps
3rd tree would probably be a tanking tree, with decent damage and heavy defense.
You can chose to play a Dragoon if that is what interest you most and with a talent tree you can chose to play the way you want. You don't need to be a Paladin to tank, you can tank with other classes using such a system since it enables different classes to fit different roles. You can even make hybrids.
I know i'll get hated by all the FFXI for making this post but i can't help to think that such a system or something similar would give us so much more freedom and individuality. My Dragoon doesn't need to be an exact copy of yours, i can do my own thing!