What do you mean by "normal content"? People were panicking that ASTs couldn't do wall-to-wall pulls, but that was totally untrue. I leveled my AST before they got any buffs and I was healing mass pulls, even with trashy tanks who wouldn't use their cds - yes, it took the entire job's kit and I only had time for a couple Gravities then, but frankly that's how healing should look imo, if you have a crap tank pull everything - you're doing hard carry at this point and that should feel like it's pushing your limits. With normal tanks it was all fine. It's not even like I'm some experienced healer either btw, it was just a matter of actually reading what options you've got and using them.
As for harder stuff, ASTs definitely did the EX trials available at the time and while there was no Savage to test with, with how little healing is required normally, I'm pretty sure two healers with 5.0 AST's output could still totally clear anything - they'd just have to dps less.
5.0 AST would've probably been a very good example to follow for overall healer power levels, if it wasn't for the other two being so "overpowered" in comparison at the time, as well as the tendency to buff things which are balanced rather than nerf the stuff that's too strong.
Don't get me wrong, I do believe that healer dps kits should be expanded again, because there's always going to be downtime, especially as people get geared up and balancing heals vs dps is a cool optimization mechanic. That said, there needs to be some actual healing to balance that dps against - we could get both more need for heals and more engaging dps.
Increasing healing requirements would also lower the dps gap between casual healers who gcd a lot and veterans who barely do so, which is supposedly what SE wants - to make healer dps truly optional. Of course veterans would still dps more due to better cooldown usage, but lowering potential max output would make weaker/pure healers far less jarring, so it's not like this would benefit only the hardcore perspective.