Until the plugin switches to storing votes differently there's going to be no nice way to sort based on votes.
Take a look at a row from the votes table.
+-------------------------------------------------------+
| ID | post | votes | guests | usersinks | guestsinks |
+-------------------------------------------------------+
| 1 | 1234 | ,1,2,3 | | | |
+-------------------------------------------------------+
All the votes for users are being stored in a singular column(votes), and MySQL has no proper way to split, count and order based on that column.
Perhaps some MySQL ninja can create a procedure/function to do it, but that's beyond my SQL know-how.
Not sure why the author choose to store votes that way, but from a result sorting perspective that's a poor DB design decision(imo).
I appreciate i havn't really addressed the question, but thought it might be nice to point out while it may be something that is easy in theory, there's a good reason the author hasn't provided this facility with the plugin already - his db design makes sorting based on vote extremely hard(at the SQL level at least).
This is what i'd do if i was writing such a plugin..
Use one new table for holding just the votes, all votes..
Here's some imaginary data in the table.
Table: wp_post_votes
Type: new
+--------------------------------------------+
| ID | post_id | user_id | type |
+--------------------------------------------+
| 1 | 123 | 10 | up |
| 2 | 123 | 22 | down |
| 3 | 123 | 4 | up |
| 4 | 123 | 1 | up |
| 5 | 25 | 6 | up |
| 6 | 25 | 10 | up |
| 7 | 25 | 1 | down |
| 8 | 25 | 2 | up |
+--------------------------------------------+
Alongside that i'd use usermeta and postmeta to store vote counts for both the posts and users voting.
Here's some imaginary meta data to help visualize.
Table: wp_postmeta
Type: core, existing
+-----------------------------------------------------------+
| meta_id | post_id | meta_key | meta_value |
+-----------------------------------------------------------+
| 512 | 123 | vote_count | 4 |
| 513 | 25 | vote_count | 4 |
+-----------------------------------------------------------+
Table: wp_usermeta
Type: core, existing
+-----------------------------------------------------------+
| umeta_id | user_id | meta_key | meta_value |
+-----------------------------------------------------------+
| 443 | 1 | vote_count | 2 |
| 445 | 2 | vote_count | 1 |
| 442 | 4 | vote_count | 1 |
| 444 | 6 | vote_count | 1 |
| 440 | 10 | vote_count | 2 |
| 441 | 22 | vote_count | 1 |
+-----------------------------------------------------------+
That way the posts could be sorted based on meta value and additionally leveraging the meta tables would mean quick access to update and fetch functions, like get_user_meta, get_post_meta, update_post_meta ... and so on..(i'm sure you get the point).
Just thinking out loud, because your question had me thinking about how i'd do it differently..