I don't know Queen well enough to assess Deaky's versatility
Well I do know that Queen flirted with just about every stylistic element you could think of. Check out this resume, I included not only the different styles, but different sounds and techniques as well:
Metal/hard rock (Gimme The Prize, Dead On Time, Let Me Entertain You, etc.)
R&B (Cool Cat, One Year Of Love)
Jazz (My Melancholy Blues)
Pop (My Best Friend)
Vaudeville (Lazing On A Suday Afternoon)
Middle Eastern melodies (Mustapha, Innuendo)
Long epics (The Prophet's Song, Bo Rhap)
Short anthems (We Will Rock You/WatC)
Blues Rock (See What A Fool I've Been, Sleeping On The Sidewalk)
60's British Invasion style (Funny How Love Is)
Folk (The Night Comes Down)
Symphonic/orchestrated power ballads (Who Wants To Live Forever)
Plus there's a ton of other weird things that can't even be categorized, like All God's People, March Of The Black Queen, etc.
Now, I'm not sure how much Deacon changed his style around to fit all of those, but it's definitely worth looking into.
Queen were absolutely fearless
when it comes to experimenting with different styles and sounds. They might even surpass the Beatles in this area, imo...