The ME1 port was done by Demiurge Studios (sp?) and the ME2 port is done by Bioware. The port could definitely have been done better ... For one, Bioware seems to forget that mouses are more versatile rather than just point and click utilities.
The ammo system (okay, okay, the "thermal clip" system), at least in game, revolves around the fact that apparently the geth found that most engagements were decided by who could pump out the most amount of bullets faster. They invented the thermal clips and then, all the gun manufacturers liked it and incorporated it into their own system. Of course, there should still be SOME types of the old weapons floating around but they never seem to appear. Meta reason, Bioware tried to make this more shooter-y, a shooter with RPG elements, in order to appeal to the Modern Warfare crowd. Definitely a different feel to the game.
The ammo system (okay, okay, the "thermal clip" system), at least in game, revolves around the fact that apparently the geth found that most engagements were decided by who could pump out the most amount of bullets faster. They invented the thermal clips and then, all the gun manufacturers liked it and incorporated it into their own system. Of course, there should still be SOME types of the old weapons floating around but they never seem to appear. Meta reason, Bioware tried to make this more shooter-y, a shooter with RPG elements, in order to appeal to the Modern Warfare crowd. Definitely a different feel to the game.