To get a skill of designing model that has amorphous surface,

To get a skill of designing model that has amorphous surface, like animation characters or figures, I’m thinking about learning BLENDER.
Do you guys recommend Blender for it?
(I have intermediate level of Solidworks.)

I’d like to hear opinions, before I decide to move steps.

Yes that is what Blender started out as. So it is a good choice.
Or you could try Rhino3D.
It simply depends on what you are used to and how you think.

For what you describe Blender is probably a good choice. There will be a learning curve but you gain new skills and have another tool in your designer’s toolkit.

I don’t want to learn all the skills that Blender provides, just modeling for 3d printing.

It would not be necessary to learn all of Blender in order to create for 3d printing. I began using a tutorial for about a week or more and learned enough to create and edit 3d models. The references in the tutorial at the beginning are aimed at creating and editing and almost nothing about animating or other aspects of the program. You would have to do additional research via the 'net or the 'Tube to cover any gaps that appear in the teaching.

@Fred_U Thank you very much! I’ll look into the site.

What about Zbrush compared with Blender? regrading sculpting.
I found buying Zbrush comes with Wacom’s Intuous 3D which is I’m interested in also.

Another free program similar to Zbrush and Blender is trueSpace. It is older but very capable. I find it very easy to modify STL files in that program. It has some very powerful tools to do exactly what you are describing.