Shall refrain from being so quick to gloat. City still have a formidable team and even if they are short of established defenders, there are other options. For example, what do we know about their youngsters?
Football is a team sport and if Guardiola manages to find a good formation that protects his "lesser" fullbacks well and play to their strengths, they will still be a threat. LCFC wining the title with no "world class" player is a relevant example of the system being more important than any individual.
And yes, I do not think that either Vardy or Marhrez is world class. And their stock rose because of Leicester's team performance over the course of the season.
All in all, I will not write City off just because they lack established defenders. That seems too simplistic as there are so many ways around it.