You, sir, have clearly not done any of these fights when they were hard (e.g. when you had relatively bad gear). Saying 'the fight is easy because all you need is to play properly and execute the strat' without armory link just makes you look like a YT hero, nothing more, and also makes all your arguments to be something comming from a player who is used to outgear content or do it when tons of tactics are around.And I hav to say your really getting my point wrong if you think its about being lazy or broke to respec. If your wiping at 70k for Ultratxion then your dps arent trying hard enough or your not healing well enough. For Ascendant Council your extra healing that you hav taken out of to put into Pers just lost you that amount of healing over the raid that would hav gotten you the kill. For Valiona im just going to lol at because that fight done correctly was just so easy even before it was nerfed. Nef is the same, all you need is for your healers / tanks / dps to be playing properly and for you to execute your strat in order for a kill. Your less then a % spell damage reduc did not wipe you or prevent you from killing boss with less then 500k health.
There are plenty of ways you can avoid dying if its getting cut that close just dont be derp.
Also speccing into Pers is like taking one step forward and two and a half steps bak, its not worth it 99% of the time.
The poster above basically summed it up for me. You are looking too much at the numbers. When they might be good, sometimes they are not that one tool to evaluate a healer. How do you evaluate a dispel? Nature's Swiftness? You can't. Same deal with Perseverance. You prefer to take mediocre (at best) throughput talents over utility and back it up with numbers. How is that even working, please explain?