This may not be precisely what you want.
Preferences: Look and feel: Tag Browser (a tab)
Partitioning method: First letter
Collapse when more items: 15 <play with the number a bit downward
And think about doing (using):
Categories with hierarchical tags (This means many column types)
eg: Science Fiction.Military, Science Fiction.Movie adaptation
This makes a Tag Science fiction with 2 sub tags
Oh, and clean your tags of all the 'still on paper cards' type crud
(the above would use 3 card minimum for category). Your computer will find them with either Science Fiction or the sub tag
Right click the Tags section: Manage and rename or delete (it is smart, and will Merge those into existing, delete if already assigned to a book (no doubles of the same tag)
And while the vacuum is out
... All the alternate spelling/slang: SF, Sci Fi, SyFy...