Sure you can learn the bulk of any class running POTD, you'd still be best served running some dungeons however at some points. There are finer points you'd never learn in a even dungeon either however. Shirk usage for instance as a tank or swap mechanic practice. You could nail down most agro mechanics in POTD or dungeons though. Same could be said for some healer mechanics.
Don't stress too much about it. Learning a class isn't nearly as hard as people make it out to be online. Unless you're doing old endgame raids or current EX primals, the difficulty spike isn't crazy.
Don't stress too much about it. Learning a class isn't nearly as hard as people make it out to be online. Unless you're doing old endgame raids or current EX primals, the difficulty spike isn't crazy.