I’ve thought that before but I don’t think it’s the case (about drops depending on what you are using). But I would advise you not to give up on ARs, especially with Roland.
He’s my default character. I love playing him. And he has damage and other buffs in his skill tree that make ARs some of the deadliest weapons in the game. I have a Pearl Havoc with 408 Damage, 12.5 ROF and a mag size of 72. With my AR buffs, the mag goes up to just under 200 and I can easily lay waste to pretty much anything, and often multiple enemies, too, on Pandora with a single clip. Even the biggest, toughest Spiderant Badass is no match and human enemies, including Super Badass Atlas Troopers, don’t usually even manage to get a shot in as I’m piling in the critical hist to make them flinch almost constantly. I’ve even taken out Knoxx with this rifle and it was quicker than when I used my Pestilent Defiler or Maliwan Crux.
ARs need you to invest time and skill points in them. They generally have a fair amount of recoil, which can make them a little tricky to use at a distance at first. But persevere and that recoil comes right down, and if you invest the skill points it can end up almost negligible. And then you will find that you can just concentrate sustained fire on crit points and everything becomes easy. You know the Dev chest in Rust Commons West, the one where you effectively jump off the map? Well, I tend to walk to it from the spawn point near Tannis, with just my Pearl Havoc, and wipe out all the Spiderants as I go. I don’t even need my turret.
ARs are generally poor at elemental DoT. With the exception of Ogres, with their fantastic Explosive proc rates, and the Serpens, with its strong Corrosive element, you will usually find better SMGs or other weapons for elemental damage. But they excel at DPS and withering fire. It depends on your play style but I usually avoid any with an accuracy below 90%, as I like to shoot from a distance. I always look for a scope, too, and the larger magazine the better (although as I said with the right skill points invested you can increase that anyway). Glorious (or Pearl) Havocs are normally among the best. Massacres aren’t bad, too, but I’ve found nothing to compare with my Pearl Havoc.
As far as Legendaries go, with a Roland build he can make excellent use of Ogres, and since nothing on Pandora is immune to Explosive if you find one it will be pretty much the only gun you’ll ever need! I’ve found a couple of excellent Destroyers, too, and with their high firing rates they can usually take down most soldiers with a single clip. I’ve just remembered I have a Shock Destroyer which I sometimes use to take down pretty much all non-Shock humans. One clip, one enemy! Regen ammo will probably be your friend, here. I usually use a Support Gunner mod and never run out of ammo.
Sorry for the long post, but I strongly recommend you invest time in your ARs. A good one will excel at both long and short range and can even replace many snipers. With my Roland, they are my favourite weapons in the game.
Incidentally, how’d it go with MINAC? 
