Bioware listens, and Mass Effect 2 is proof. Nearly every common complaint about Mass Effect, from the half-hearted shooter mechanics to the messy closet of an inventory system to the tiresome Mako missions, has been addressed.
Mass Effect 2's shooter side plays something like Gears of War "light" so to speak. This isn't a bad thing. The weapons no longer respond to hidden die rolls of any sort. Each weapon has certain characteristics, and those are not modified by Sherpard's level or the weapon's level. The result is a game which feels more connected to the player's controls than the original Mass Effect. Bioware could make a straight-up shooter with these mechanics if they wanted.
Exploration has also been streamlined. The universe of Mass Effect 2 is still huge, with many planets to visit, but extracting resources does not require a personal visit. Instead, players can extract resources from planets using probes. See this Exploration and Mining Guide. Should there be something of interest on a planet, the game indicates that there is an anomaly detected. Shepard then can land and explore. These mini-missions are not common, but they are far more unique than the dime-a-dozen quests of the original Mass Effect.
While much of the game has been streamlined, there is a new research mechanic which allows players to obtain upgrades to weapons, armor, and abilities, and inventory is handled through a pre-mission Load Out system highly reminiscent of shooters. These mechanics take the place of the typical role-playing approach to inventory which was featured in the first Mass Effect. It does its job well, but I do sometimes miss the excitement of finding a new piece of armor or a cool new weapon, which is now a very rare occurrence. The randomness of finding loot on a mission is always exciting, and the research system in Mass Effect 2 can't replicate it.