ME1 was another step-between-steps in that way, there was still quite a bit of dice-rolling going on, which made the shooting feel decidedly less-than-great. (It's still my favorite ME game.)You can see why in Mass Effect they made a conscious move towards action gaming mechanics for the combat since it's just so much more engaging, even in ME1 when it was still very janky.
The only dice rolling I can recall was to do with where a bullet would land in the given cone of fire. In that sense I put it as being closer to the (original) Deus Ex style of RPG combat where you have access to all the guns but are bloody useless (wide spread, unstable aiming) at them unless you invest points in a particular skill.
Regardless of all the changes in ME2 that went too far for my tastes (e.g. getting rid of the inventory instead of simply making a better UI), the changes to the core gameplay and shooting mechanics were most sensible.
I definitely didn't miss the inventory system being yanked out. It did nothing but create a chore common to too many RPGs whereby the inventory gets filled up with useless junk and you have to tediously figure out which piece has *slightly* higher numbers than yours or your party's gear and sell all the rest. I played on PC so the UI was never really a problem.
ME3's system of unlocking, incrementally upgrading and modding new weapons and armour pieces struck just the right balance IMO. The only think I would have preferred they did differently would have been mod slots for the armor too and a way to manually alter the cosmetics on the weapons. An upgradable omni-blade would have been good too.
That said, I do think in ME2 they somewhat threw the baby out with the bathwater and oversimplified too many of the systems.
It's interesting (and frustrating) how each instalment got one thing right, but compromised another. It's like watching a tug-of-war between the demands of design, user experience and practical resources over the course of the series.