The main thing with GB is it's different, especially the Prem.

Specifically, the magna slings react differently to standard slings and interact with the ball differently. Sometimes they basically throw it down the centre or outlanes, but just as often they treat the ball more 'sympathetically' than a standard slingshot - however the haters only ever remember the drains.

I can't think of another machine which has double inlanes on BOTH sides separated by the wireform with no rubber, this does make it much more likely that you have little control through nudging to influence the ball. Again different than the majority of machines.

The flipper gap is not as much of a problem as people make out, I'd bet there's a similar percentage of ball drains down the outlanes as the majority of other modern machines. Putting a centre post in just seems like desperation to me, but each to their own.

It's as linear as you want to make it, although it requires more thought as to which mode you start next, as it's dependant on the shot you used to finish the last mode.

I just can't defend the right PKE ramp. the angle of entry and steepness is all wrong.

I don't find the shots any narrower than any other game - I don't have any more trouble hitting them than any other.

Scolari brothers can be annoying, but's it's in your power to a) trigger them and b) dispatch them - I don't see the problem.

Lots of people complain about bugs in the code, I think the main problem isn't bugs - but the unbalanced scoring - especially the skill shot for 10% of your score. Put up a great 1st ball and it's a massive game changer. The short plunge exploit / playfield validation doesn't help either, but that's hardly unique to GB - I'm looking at you GoT. I see no reason why that can't be amended in the code. As soon as the shooter lane switch is triggered, then untriggered, the playfield is valid, Iron Maiden does exactly that.
If you're worried about a flaky shooter lane switch robbing people on site - have it so that it's a setting, which is automatically on in Tournament mode.

It's a game which generally produces short ball times, so what? Not every game needs to last for 30minutes plus. The fact that there is a lot to do to get to Wizard Mode, coupled with the short ball times means a lot of people won't get there and resort to 5 ball games, or centre posts being fitted. Not every game should necessarily be designed that everyone gets to wizard mode every few games. (IMHO I think the new code for Aerosmith sucks as it makes the game FAR too easy, but that's getting off topic)

Basically, It's not the best game out there, nor is it the worst. Plenty to do, great soundtrack, great dots (which should look even better in colour), could do with a bit of polish in the code.