Well, for me, what makes a mod really successful is the quality/execution.
When I say that, I don't necessarily mean the purpose or idea behind it, but how well that idea is carried out. For example, if you make a quest in a mod:
How good is the dialog (Any spelling issues, accurate punctuation, odd or "unusual" (not generally known by the masses) grammar, phrases in the wrong order?)
Is the quest structured in a realistic or detailed way? (Is it too long, are the goals not really connected, are you crossing lots of areas just to grab one little piece?)
Are the characters well thought out? (Backgrounds of a suitable length for their role or whether they are minor/major characters, any oddities related to the character executed well [such as a slight slurring of certain sounds, or a favored tone of voice])
Or if your mod is more for texturing for instance:
Do your textures "mesh" well? (Can you tell where the seams are, do the textures tile well?)
Do the textures for the area (if doing a module) all fit together well, or are they somewhat jarring where they're placed?
What sort of feel do you want in the textures, and do others get that same feeling when looking at them?
Blog #8 - What makes a mod successful?
in Sith Holocron's Blog
A blog by Sith Holocron
Posted
At all I agree with this. Explained answer