Although I enjoy combat rolls, I thought they weren't well implemented in ME3. Enemies do way too much damage, so most of the time I'm too busy being behind cover to enjoy the expanded move set. Not to mention it's way too fast, it doesn't feel right. And although Nova was a good addition, in some ways it took away some of the fun of Vanguard. In ME2 the weapon was a much bigger part of the gameplay.
And I find it funny that you brought up slow motion! It feels natural playing a Vanguard in ME2, a quick change to line up a good shot, different from ME3, in which everytime your barrier breaks the game slowns down and totally mess with your gameplay. That's one of my biggest complains with ME3... can't understand why they did it, or at least why it can't be turned off.

(I just wanted to use this gif, all in good fun!)
Oh I don't deny the faults of ME3 either and I do think ME2's game play was balanced well, but I liked the higher mobility afforded to all classes (Glorious multiplayer in particular) in ME3 even if I only used the rolling as a a quick cancel into cover or to another piece of cover. Unless you were nova-cancelling into them, combat rolls out in the open were rarely a useful tactic unless you were avoiding a melee unit and weren't being fired on en masse. The faster gameplay felt right, but I can understand how more RPG-oriented players could be irked by it, especially those people who would consider ME1's gameplay to be the high-note of the series (which, I'm sorry you people but I just don't see it).
The slow motion barrier aspect irked me greatly as well, as does slow motion in shooters in general. Between Barriers and when Shepard used a heavy melee attack and as much as I liked the Running heavy melee of vanguards, having the game slow down whenever you used it just wasn't fun for me., which is why I'm glad slow motion isn't a thing at all in Multiplayer inb4 lag hue hue. I feel that the multiplayer helped highlight the gameplay's improvement across the series while trimming out some of the rotten fat that still clung to the good marbled stuff.
I'm always resetting my Novaguard in ME:MP to alternate between being a Power Build, Sniper Build, and Melee Build which isn't exactly something you could pull off in the prior games. Vanguards were largely 'Spam Powers and shoot Shotgun' (or for many, Power and Pistol) in the first Mass Effect, and I do think that they are the class that's evolved the most throughout the series (hence why I always refer to them). In ME2 it was mostly 'Charge, shoot with shotgun, then either run away or walk in circles and shoot.', with the gunplay being much better than in the pure number-based ME1. In ME3 it tends to be, based on power list (SP or MP) 'Charge in, Melee, shoot other guy, roll while going into a charge, get into cover, shoot, cover grab, charge into heavy melee, shoot' then maybe throw in a few novas about. . maybe swap to Sniper Rifle if you're carrying one because it can actually be viable if you want to be an 'all-range killing machine' versus a Melee-Range Menace. . .there's more diversity overall in ME3, and the important kind too.