Likely you're still playing like you did when you were 'good' at level 20. It worked for you well, so why would you change it? Unfortunately as you leveled you got new abilities, as did your opponents, and they are now using those abilities to make you look 'bad.'
So in short, yes. You got bad in the process of 20 levels. Op healers are better than sage healers except for AoE, are worse than Merc healers because they lack their mitigation, and will be the best healers in 1.2. Your class is not bad.