I didn't read a single post here that told the OP to not use Cures. I pointed out using Cure II over Cure I, but that is the extent of it. The OP has also expressed his interest in taking WHM into endgame, so optimization and min/max is going to be very important, and it's best to learn it sooner rather than later. But striving to play optimally is going to put you a cut above the rest of the healers in PUGs if even only for the courtesy you're showing your other party members. They will appreciate it. Trust me.
A lot of min/maxers will say that min/maxing doesn't matter for anything outside of savage/ultimate. The ABC rules applies heavily here because they look at every single second during an encounter, and if your GCD isn't always ticking down, you're wasting everyone's time. This is a much different mentality than what's being proposed to the OP here. I oppose the meta mentality, but only the thought processes that lead to exclusions and elitism. I don't oppose optimization by any means.
That is not to dismiss your post though. A lot of healing is reactionary. Especially for WHM, and even more especially in 24-man content. While I feel that savage content tests your ability to memorize an encounter; alliance raids is where it's at to test your ability to react to damage that is not part of the script. In chaotic battles which are common in alliance raids, it can (not always) make more sense to hold on to certain abilities or sit on a couple of GCDs to evaluate the situation. But you still want to ABC as much as possible.