1) All I know is I played AST from the day it was released and gave up around level 51 because I just could not keep up with the damage the tank would be taking in the level 50+ dungeons even though I was using good gear I'd obtained from it when playing it as WHM. Doing the same dungeons as WHM was a breeze. When I came back after 3.1 not even knowing the potency was increased, I was surprised at how much easier it was to play and how it felt like WHM now. I hadn't even touched it in forever, then just did Dusk Vigil and it was completely different. Maybe it was because others were better and the dungeons weren't as new but I actually went online specifically looking to see if they upped the potency because it was like night and day and I knew something must have changed. By the way where did I say that a potency increase to healing spells was the ONLY change they made? I said they increased potency, so spells, cards, whatever. Pick my post apart as much as you want but at the end of the day they improved the class at 3.1 because everyone hated it and since then you literally have to hunt on here to find a "Why AST sucks" post when they were every other one pre 3.1.
2) Do some research, this was revised as everyone on here said the same thing that you couldn't do it while the cast bar was up. One of the first results for "ffxiv disable" on Google (
http://ffxiv.gamerescape.com/wiki/Disable) still even says "Reduces the potency of the target's NEXT action by 10%." Whether it always has done it while the cast bar is up is not relevant, do a search on this forum and you'll find tons of people asking the same thing. So even if it wasn't changed, it clearly was confusing as otherwise they wouldn't have changed the tool tip to say "Reduces the potency of the target's ACTIONS by 10%". Note that "next" has been removed. If you're already casting an attack then that's your CURRENT attack not NEXT, hence the confusion and the change.
3) My post was about LA and MP management, with a mention of a couple reasons AST got a bad rap at the start. Obviously the weak cards were there as well, but I'm not going to list 50 different reasons for why people non stop would post here about how bad it was and what made that change when my post was about MP.