I’ve completed the last Main Scenario Quests for the base FFXIV game – A Realm Reborn. No spoilers, but I will mention that you need not be intimidated by these quests as you approach them. Once you are level 50, and have the decent gear from quests or merchants, you should have no problem completing them.
After trying Red Mage yesterday, I tried Samurai today.
I had my Bard up to level 50 and so I went to Ul’dah and signed up to be a Samurai. So the first couple of quests are not that bad. After a little training with your master, some guys show up with a grudge and while the low level guys are no problem, it takes a little while to take down the big guy. No big deal as long as you avoid his attacks.