When I saw how little impact my ME1 import to ME2 had, I knew I wouldn't invest in anymore Bioware games claiming to have C&C.
ME3 was pretty heavily shaped by ME2, though. Krogan golden ending: Not accessible if you'd been a conservative research-deleting dick in ME2. Quarian+Geth golden ending: needed at least both Tali and Legion alive from ME2, and Legion was the hardest companion to get loyalty from (because of bad design, I freely admit).
each of those only differed in a single cutscene, but it was a -powerful- cutscene. undermined completely by the ending that asserted that the game'd been about a theme it never had been, of course, and Shep not being able to say 'wait a minute, all you need to do is shout at robots to make them and meatpeople be friends.' but leaving aside the anemic ending, ME3 put some real production cost into rewarding playing well in the previous games with better outcomes in the third.
Bioware is capable of some great moments. if you didn't have an emotion at Mordin's several deaths in ME3, I'm pretty sure you're not human. that they don't turn those great moments into great franchises is a mystery--is it budget constraints? is it that they just luck into genius fleetingly? no real way to know. but it's a mistake to say they can't do anything right. they just can't do -enough- right, and their scope is so triple A epic that they can't keep things subdued and concise enough only to use the bits they do get right.