1. Dont worry about class choices. Performance and skills in FFXIV heavily rely on wether you like the class or not
2. BLM is more than viable. There is only 2 reasons why ppl are salty about them:
- BLM is self-centered. Aside from some mana now and then, they only contribute 1 thing ... damage (though they are ofcourse the best at it )
- There are 2 types of BLM. Bad ones and amazing ones. Unlike other classes there are very few people in the "medium/decent" grey area in between

So... if you like BLM, just keep going and ignore others :P