My son picked up universal remote from Xur Friday. We tried a few setups and found running a high impact sniper and a heavy machine gun with it worked pretty well, but you have to really monitor your ammo. With the maxed range settings, as maxed as we could get it at the time, It was good for the short range. We used the sniper for long range and high damage to make up for the heavy slot. The machine gun was really needed to cover mid range and high enemy count situations. Still not recommended for end game content though. Still wouldn't want to run a short rage shot gun either. Way to up close and personal.
Some situations a double shotty can work well. For example glimmer farming in VoG gatekeeper or Mars exclusion zone.
Otherwise my experience agrees with yours. You need a Sniper for mid to long range and some kind of a HMG for swarms at mid ranges.
I totally agree with this, my glimmer farming loadout for exclusion zone is voidwalker (obsidian mind) with universal remote, a sniper and rocket launcher. Universal remote one shots the lemon bar legionaries, centurions, and can most times kill a phalanx with a well placed leg shot. The sniper cleans up the trash that won't come to you, and the rocket is for suicide if you accidentally kill the centurion.
With Obsidian Mind you can run past the first dropahip to the first set of Tier II legionares on the left and kill them all in one shot.
Then if the ones on the right are clustered up use a rocket, else a shotgun or hawkmoon. Charge the regular phalanx from the first drop ship and use a scatter grenade at your feet while standing next to them. Easy Peasy.