Quality of Racing = Having cars with faster pace behind slower cars.
There is no matter how this is achieved (safety car, rain, tyres, different strategies, technical problems), it will lead to great races.
F1 has become more and more predictable and it rarely happens that a faster pacee car ends up behind slower ones, that is why the racing is so boring.
Option 1: Safety Car
The Safety Car does no longer bring any trouble to the lead car, because with the speed limit and open pit lane they will not use any time/positions for pitting unless they actually catch the Safety Car like Lewis did in Monaco. The closed pitlane was another fun factor which could lead to different strategies, but Renault...
Option 2: Rain
Safety Car and ultra durable and versatile Intermediates have destroyed the unfluence of rain to races.
Option 3: Tyres
Tyres are too predictable, teams have figured them out and are rarely running into problems by a wrong choice and if they do, they claim it is the tyre manufacturers fault.
Option 4: Different Strategies
This still works, but because of the dumbed down version of the first the options there are less variables...
Option 5: Technical Problems:
Last year Montreal was great with the Mercedes struggling, but these kind of problems do simply not happen often anymore because of the durable parts that are nowhere near the technical limitations.