I'll post ion more detail when I get home, but there's a flaw in the premise that Sahdowrun is Alpha Strikey. Specifically, that this is not the case (by design) is SR5. Fights last a good deal longer in terms of in-game metrics (while taking less time out of game, interestingly enough).
As for damage staging not being needed: you don't need to increase base damage to let higher skilled characters pull ahead (though, if that's your goal, it's the called shot rules you want, not the burst rules). Defense pools are a good deal higher, but hitting just once with an assault rifle carries a real chance of killing most targets, and if your dice pool and modifiers are high enough, there remains the possibility of dropping multiple targets.
By if your dice pool is high enough there remains a good chance of hitting multiple targets do you mean using your gun to multiple attack two different people and splitting your dice pool?
If so please tell me, when you do that, do you acquire twice as much recoil as if you fired at one target?
More to the point, how can start and argument with saying 5th edition is less alpha Strikey and the close with a comment of how hitting once with an assault rifle carries a real chance of killing most targets?
If you can kill someone with one shot, and a good burst makes dodging next to impossible (defense pools may be higher but not high enough to give someone any real chance of dodging up against a -9 dice penalty from a full burst) this is the very defintion of alpha Strikey in my book (what definition are you using I use it to describe a system where defense is a sucker's game and its all about hitting first and hardest).
You are correct that called shot rules can let you do that, if you're using a sniper rifle or some single shot gun, in 4th you could in effect do it with automatics as well.
The lack of narrow bursts is why I am considering rerolling my character from Origins with all the extra yen and karma I earned (a one time thing we can do because there were no books out when I built my character) into possibly a longarms specialist or maybe I will stick with automatics and just suck it up and split my pool while using full bursts so that the fact that I have a smaller pool to attack with is offset by the fact that they get no pool at all to dodge with.
But once again I have to ask does recoil double/triple if you multitrack two /three targets, as I am not sure if it does or not at the moment.
First, I am of course referring to splitting your dice pool - that's the only way to achieve an attack against multiple targets. And no, you don't get twice as much recoil, because you haven't fired any more rounds.
Second, you have to consider things holistically - one system in isolation tells you precisely nothing. So, let's say you decide you're going to be firing full auto. Your target has, say, Intuition 4 and Reaction 4(6). He is also hiding behind an object that provides good cover (because he's not an idiot). Lets give the Sam Agility 6(

, Automatics 6, and a wireless smartgun for 16 dice, along with an Ares Alpha and a Strength of 4 allowing him to absorb the recoil from 5 rounds. As he fires 10, he's at -5 from recoil. He is further subject to a -6 penaltiy for blindfire, dropping him down to 5 dice. And just because I feel like it, the target is 28 meters away. The target loses 9 dice to FA, but gets 4 from his cover, and is using the Full Defense action to add his 3 Willpower. Meaning he's rolling 8 dice to defend against 5. His odds get even better if the sam has to instead shoot through the barrier. AND the sam doesn't have a Simple left to grab cover, so he's in trouble.
That doesn't sound like a sucker's game to me. In any case, a better definition of alpha strike is a tactic in which you unload as much offense as you possible can in the opening of combat, to the exclusion of anything else. In some mech games, for example, this refers to firing all your weapons at once (such that you cannot fire at all until one of them comes off cooldown). An alpha strikey game is one where this is the most effective tactic - but in fact, it's a better tactic to do things like circle around and flank your opponent to deny them the benefit of their cover, while using suppressing fire to prevent them from switching position.
As for good uses of a simple action: Observe in Detail (situational awareness is absolutely crucial), Take Aim, ready a grenade, throw a smoke grenade, ready a melee weapon (useful if you expect to need to make use of Interception)...
Anyways, as to armour: Any item that offers +Armour is limited by Strength. For example, if you want to wear a helmet and use a Ballistic or Riot Shield, you need Strength 8. Run and Gun will almost certainly expand the list of such items.
And at the end of the day, just pulling the trigger a whole bunch isn't a way to win a fight against a reasonably intelligent opponent. Tactics matter.
I do expect to see more people using Longarms now, though, because it got a much needed upgrade so that it's actually competitive.