Change your favorite series to be like the others.

[C.E. Evans]

TOS:

TNG: More of an ensemble cast rather than a big three.
DS9: Some storylines spanning two or more episodes.
VOY: Female captain.
ENT: The Enterprise as an Earth starship, not a Federation one.

 

[Temis the Vorta]

So...the idea here is to screw up your favorite series by importing elements from inferior series? Nah, too masochistic for my tastes.

How about taking your least favorite series and improving it with elements from the others?

For instance: VOY

from TOS: charismatic kick-ass captain who is not bipolar
from TNG: uh...maybe bring in Data to be buddies with EMH?
from DS9: serialization, intelligence, dramatic oomph
from ENT: beagles

 

[Anwar]

So...the idea here is to screw up your favorite series by importing elements from inferior series?

No, it's to get over the silly conceit that one of the series was perfect and none of the other series had any redeeming, let alone interesting and appreciated, traits that would work out well in other shows too.

Okay, VOY's not my favorite but I would incorporate thus:

TOS: Smaller central cast

TNG: All characters actually do something and enjoy their roles.

DS9: Make the story scope more grand.

ENT: The serialized story arcs. I don't mean making the whole series one big serial but the 2-3 episode story arcs (and not forgetting the events afterwards) would be preferable.