Are there other strength programs that sprinters could use?

Most certainly. 

Are some even 'better' than the Ross protocol?

Others will probably say there are.

Is it as simple as the deadlift?

Most will say it's far more complex than that, and have indeed made that statement.

Are they correct? 

Many believe that pictures are worth a thousand words.  In this regard, I'll let the following pictures speak for themselves.

When I began the "Barry project" over two years ago I was skeptical for the same reasons listed above, as well as many others. But  I agreed on giving the program a "beta-test." The subject for that test? A respectable two miler (10:03) who had not improved his fly 75 speed in three successive years, and who had never 'touched' a weight throughout his high school career. If this athlete could get 'strong'  from early December to late March, and if I could see appreciable, measurable differences in his fly 75 speed doing nothing different other than the Ross protocol, then I'd consider implementing the program.

Note the first two images from the opening day of our training session.  He looks terrible at 50% of his body weight, and struggles mightily to lift his own body weight.  Everything is 'wrong' mechanically.  He's even lifting on the front part of his foot.

Now look at the last image.  

The only requirement was that the athlete had to follow the guidelines as Barry presciibed them--no periodization or 'conversion' phases, no ancillary lifts, and no playing around with sets and reps.  And I had to send Barry video clips from every training session, including the plyo work, for the first month of the program.

I detailed the complete "Barry Project" both on Supertraining and here on the forum.

Can an athlete get stronger--and more importantly--faster--doing "just" the deadlift? 

Judge for yourself.