Few "quick" answers:
Decreasing the range was something I went for because at least in my game play style, more range messes with me. My chain will always be ranged capped to the shortest range attack in my chain, I don't like starting an attack chain and realizing my next attack requires me to move closer (remember when Cosmic Burst was 60ft?) But we heard the feedback, no bueno, we reverted it. This is why we test.
The recharge was due to quite strict design rules the live team followed and we stick by. There is a damage formula, leo posted it here somewhere. If there is no special mechanic binding a power, if it behaves just as a regular attack, it is meant to do regular damage. That formula dictated the quick snipe be either lower damage or higher recharge. At the end, now we settled on adding a ToHit based special mechanic to justify higher damage at 12 second recharge.
Why not allow Aim/BU to trigger in-combat mode? For one, not everyone have those (power boost would only do that if you have a ToHit power like Tactics running.) Plus, this thread has already shown the bonus damage is desired, and you do have to try out taking out an annoying Lt with Build Up + Aim + Slow Snipe. So far, Leandro has been working hard on making the new Snipe set desirable so it does not feel like a penalty to go for it to get perma-fast-snipe.
On the delay, I covered this in an earlier post but there is a delay on some of the snipes that was not there before. That delay is still inside the 1.33 window. Outside of beta, currently, the attack fires at frame zero, before your character even moves and does the fire animation. Then you stay there, immobile, for 1.33 seconds. Now it happens at frame 17 (0.56 seconds into the animation) and you then have another 0.76 seconds to wait for the cycle to end.
Note there is the context of the shutdown there. They got fired, Millar wanted to push the issue so those last few weeks of uptime everyone could play with what was done without the limitations of the singular test server. I doubt he would had tried to push it as it was without more work had the game not been abruptly shut down.