What's the straight dope on getting other vaccines along with your flu shot?

Let’s chat about that for a second:

Is it safe to assume that there’s some sort of continuum at play here ? Meaning: why not compress the vaccination schedule and reduce the number of injections and decrease the risk of contracting the diseases for which we’re vaccinating ?

Was some sort of “dose-dependent” relationship between number of components, spacing, and adverse reactions established ? Has that been revisited as the number of require/recommended vaccines has increased ? Was a sweet spot established ? Should it be revisited ?