From a purely native speaker's (non-linguist) perspective: there is essentially no difference in the 'meaning' of these sentences. Basically they both say
It is better to show you my work(s).
Would in English is a softening word, that is, a word or phrase which makes us sound less demanding.
- Turn down that music.
- Would you turn down the music, (please)?
In the same way,
I think it would be a better idea...
is softer, less assertive than
I think a better idea would be
Because you are asserting your preference over the person who asked you about your art, the would softens the response a bit.
Semantically, I'm not sure of the difference. Would indicates the consequence of an imagined event or situation. In the first, You're imagining that your idea is better (softer). In the second, you're pretty sure your idea is better, and are imagining that showing your work is better than speaking about it.