I think thinking of "The Flash" is too small, and that we'll see multiples. That said, if they went to all this trouble and are leaving Barry retired, I'd be really disappointed.
I'm thinking of "the Speed Force" as a double entendre, meaning either the cosmic power that gives speedsters their speed, or else all the speedsters taken collectively. Thus we'd have a second comic titled "The Speed Force" starring all the speedsters except Barry, with Barry headlining "The Flash." This would mimic what was done with Hal Jordan. Only problem with that is the need, I think, for the word "Flash" to be the first word (after "the") of the titles of both books, so they sit together on the shelf. Also the double entendre might be confusing to new or casual readers. So never mind, I guess.