It's nice.

I've got one with eye of the storm and surrounded, but since shotguns have pretty much the same range it just feels like a fusion rifle can't hold it's own. You get blasted by a shotgun from what feels like sniper rifle range before you've even fully charged up. :(

Not only did that mechanic change from one game to another but I'm pretty sure Reach changed it mid-lifcycle, or it was changed in certain game modes, or something? Maybe it was just for the "anniversary" playlists that came out with CE:A? My memory's a little fuzzy on specifically when and why that changed.

Anyway, regardless of that mechanic it's generally true that headshots didn't do anything special until the shield was down. And once that happened, the special thing they did was kill you immediately.

My advice would be:

1. Stick with a Scout Rifle for a while. Preferably a MIDA Multi-Tool. Having the radar on while zoomed in will help you get a better feel for how the radar can show you the distance and location of your enemies at all times. The longer range will help keep you out of people's shotgun range. And the need to land headshots will help with your aim... mainly because MIDA won't hardly kill anyone if you don't line up your headshots...

2. Work on getting out of harm's way the first moment you take a hit you are unable to respond to. Don't worry about turning around. Don't worry about killing. Don't worry about helping your team. I'm pretty good at the Crucible but I still have to stop myself and remind myself to break off unfavorable engagements. I play significantly better when I prioritize getting away and reengaging rather than trying to eek out the kill.

Destiny can feel really fast but beyond snipers, shotguns, and rockets you have more time and ability than you might think to toy with or evade an enemy.

Exposure: Guardian shields are increased but do not replenish.

The problem with PvP is OHK weapons, not the other weapons. There is enough time, if you're using cover, to get back behind cover and avoid dying whenever you're faced with any weapon that is not a OHK.

I keep thinking about this -- MANY weapons are one hit kills if you take your target from behind -- the player doesn't have enough time to get out of the way before they are dead. Maybe this is intended. I find myself often getting killed before I can either take cover or return any meaningful fire on the target in PvP in general. Usually because you never know where people are going to spawn.

It's possible I am just not great at PvP... But this is the biggest blocker for me in PvP. By the time I see half of the players I'm mostly dead. Destiny PvP has me looking at the motion tracker and guessing where people are as often as I'm seeing someone and then shooting. This seems odd to me, and I wonder if a higher TTK would help solve some of this.

I'm sure it would have it's own problems though too.

I watch my motion tracker a lot too. A big part of it is really being aware of where your teammates are. There's no enemies in those areas or your teammates would be dead, and they'll shoot at people they see which helps you know where those guys are, too. As for dodging incoming fire, this is why things like shadestep and blink remain very powerful - they help you escape.

This is how Halos post-Halo 1 work. Personally, I love the speed of Destiny as is (and do Guardians even have shields anyway?). It's part of the reason why I've basically switched to Destiny for my PvP. The decade-long slowdown of Halo finally got too frustrating. Destiny reminds me of Halo 1, but if Bungie took it in a totally different direction. Hopefully they don't repeat the slowdown thing, although it's already kind of trending in that direction.

If you don't enjoy that, why don't you prefer one of the many other PvP games where the TTK is much shorter? Also outside of the H1 pistol, Halo 1's TTK wasn't that short...