IIRC Williams Firepower was the first to have the rollover lane changes, and it came a year or so after Flight 2000. Not sure I could call a feature that didn't exist anywhere at the time a flaw.

As for the upper left playfield space, yeah, that's a lot of real estate underused, but could say the same for Twilight Zone with the gumball machine and "Power" mini-playfield. Flaw or feature? I might suggest such games with constrained playfields on one side offer a little more challenge, as shots in that direction can quickly head for a center gap or outlane with less time to react and defend.

I was thinking FP was '81 and after BK. Oh well.

In any case, Steve Ritchie's early Williams games broke a lot of ground with two features named here that have long since become standards, such that people would say games without them are "flawed."