We've already done that in England. The only club to do the English domestic trophy quadruple.
Yet Liverpool got more credit for winning a trophy that is rigged, where a team can lose 3 games, draw 2 games, and still win the CL.
Given the choice, like any sensible and honest football fan, I would rather see City do the English quadruple in one season, rather than winning the CL.
CIty will win the CL eventually. I doubt very much the English quadruple will ever be done again in 1 season. Or at least not for a very, very, very, long time.