Wall of text incoming. If you don't want to read it, it's probably not meant for you, so just move on.
I'd understand that complaint regarding ME1.
It was interesting in that it was a somewhat effective hybrid between the two genres, but it didn't capture either particularly well. The shooting and cover elements were clunky, and squad management was nowhere near as streamlined as it could have been. A lot of features felt out of place or were simply boring/very rough, like the vehicular sections. The same can be said for the RPG elements. Armor and weapon upgrading was broken and mostly pointless. The talent points and character classes weren't particularly effective. Sidequests were incredibly generic and monotonous, environments got repeated a lot.
The reason it managed to garner a fan-base despite these faults is because the game still manages to deliver a compelling
experience despite these faults. The universe of Mass Effect is fully realized - the setting is a compelling take on the science fiction genre. The entire thing is held together by a plot that, love or hate, is populated by compelling characters that have a real stake in what's going on. All of this is masterfully crafted in typical Bioware fashion.
At the end of the day, what you get is a peanutbutter-in-your-chocolate mashup of tactical shooter and RPG elements that is, for the most part, better than the sum of its individual parts.
Now take all of those complaints and throw them out the window.
I was leery to hear about how much was trimmed or streamlined from Mass Effect 1 in the sequel. I'm eating those words now. From my hands-on experience so far (~20 hours,) Mass Effect 2 improves on its predecessor in nearly every way. The shooter elements have
indeed improved substantially - the controls are tighter, the action is more intense, and this streamlined experience
does lead to better gameplay. The pace is substantially faster, but never uneven.
RPG elements, while toned tone, have also been refined. What you get overall is a much tighter, more focused gameplay experience that is simply more refined than its predecessor. The story and character evolution returns, but the cast is even bigger and better than before. Integration with the weighty decisions you made in ME1 are fairly seamless and impact your story in a few big ways.
The bottom line is basically that ME2 is a better game. I liked the first, but was disappointed by a lot of its missed potential. ME2 utterly blows the original game out of the water and is one of the better games I've played in a few years.