Look, if you don't wanna heal with beorning, you don't have any interest to even gear it correctly for healing and thats why you have trouble healing even easy content like FI's.
I heal Thigil Gundu T3 with my beorning and I can say that it's easy. You have HoT on tank what pulse every 3sec and it does 20-60k heals every pulse depending if it crit or not. That HoT alone is more than enough healing for many instances. Then you have splash heal what refresh your HoT what can do even bigger heal, roar can crit easily over 70k heal. And then you have bellow what also can crit over 60k and it can do that to every party member.
Man form things aren't that good but mending can crit also 60k and it has shortest CD of all healing skills. Hearten isn't strong but it still can do way over 10k crit pulses prolly even 15k if maxed outgoing healing what I still don't have and it pulse every second.
Soon maul is fixed so it also heals beorning what makes it very good skill to use when everyone has taken lot of damage. Maul crit pulses are way over 30k and it does 7-8 pulses.
So I really don't understand why someone have troubles to heal with beorning? Do you know that you actually need to max your tactical healing rating from your carving and add healing rune to your relics? They do a big difference now as you can see this picture. 1st row is with healing rune and maxed tactical heal rating and maxed healing legacies, 2nd is just with maxed healing legacies.
https://www.dropbox.com/s/0gk9ctsig9skt2y/scaling.png
There was time when tactical heal rating didn't matter for beorning, maybe you are not aware that it was fixed recently.
Mini or RK just can't come even close to HPS what beorning can currently push. Before beorning changes, we was already top on that chain and now we are even more ahead. With this change they increased beorning heals and increased cooldowns little, but not enough because our heals went up, not down. And in my opinion that CD increase was bad move anyway, it makes beorning healing even more burst what is already was. I would like to see heal values nerfed and shorter CD's that way we would get more steady healing and we could actually spot heal better party members who needs healing. Currently you need to rely quite much to Abyss 4-set bonus to take care of party healing what it does very well.
Beorning who doesn't have that Abyss set, will face troubles trying to heal full group without cappy.
I would say that Abyss set actually made beorning a good healing class at 115 followed with mini nerf what was very much required and requested long time. This direction where beorning is going, is making beorning very OP healer just like mini was.