OPINION only!
From a Scholar perspective, I think the CC system is just right. Resistance duration trait is a must on healers, so it should be every 15 seconds.
Against Paladin: their 3 second stun makes Purify a much better choice, you can get at least 2 seconds off the stun. Silence isn't very effective against scholar because you have Lustrate. The idea is to focus on Broil-Lustrate or Adloquium healing and when silenced use Lustrate.
Against Dark Knight: since their stun is only 2 seconds, Purify might not be as good.
Using Purify before they stun you can also work, but requires a lot of skill. This works, I think, because the tank actually already stunned you on the server, but it has not shown up on your screen yet. So if you know a tank will stun you you can use Purify and have the stun debuff removed almost instantly. Of course this is a huge risk, and if you fail they get a full stun on you, but sometimes you just know it will work and feels amazing when you pull it off.
Tanks that try to CC the healer very often can be countered easily with Concentrate.
When a tank CCs you, they can't CC your team's DPS and so they do full damage.
Keeping notes about enemy tanks is a good way to keep track of their playstyles. You can adjust your additionals based on the player, not the class.
I think a lot of the complaints about CC are too one dimensional. If you're being CC'ed you should expect your tank to also be CCing the enemy. For example, your tank may have stunned the enemy healer just as you were stunned - now the situation is even. If your tank doesn't CC as well, then your enemy tank is just better, and they should win. Some games cannot be won and can be frustrating. Making sure you're focused on playing your best, rather than the unfairness of your team makeup, is in my opinion the most important thing to improve as a player. Complaining about how your team isn't ideal probably means you aren't focusing on what you should have done better that game.
I think making fun jokes about how your tank overstacked, or DPS did no damage, is fine because you probably had no chance to win the game. But you shouldn't do this in games that could have been won if you had played better. Very often when a player says "I couldn't have done anything", it's not true.
For example:
When playing against monks, if you know they can LB, staying close to them is a good idea. Usually monks will use their burst and then immediately LB. This gives you a window to knockback them to stop the combo, delaying their burst-LB combo for a while. But if you're positioned far from the team, you can't do this, and the monk might kill your party member.
Situations like this are also a mistake, and you could have done something about it. You could blame the Paladin or Dark Knight for not protecting your party member, but you had a role in that too.
Staying around the walls to "dodge" melee and caster LB is also another technique that can only be used if you're positioned correctly. If you succeed, you gain a huge advantage for your team because the enemy DPS wasted their LB.
Another common situation is when your melee is positioned so that you can't heal them. You can call this overextending, but it's also your job to be in position so that they can be aggressive. Positioning is an incredibly huge factor in this game. And so despite the fact that there are only "9 buttons" or so in this game, saying that you played perfectly is probably incorrect, so I believe there is no skill ceiling in this game. Maybe in pressing buttons and rotations, but definitely not in decision making.