I see what you're saying, but the part about Barca's interest is misplaced, i said this in another thread, their transfer strategy has been all over the place the last few years, and players like Arda, Gomes, Alcacer, Digne, Vermaelen, who were supposed to be fighting for starting roles were found not to meet the required standard. There's no telling how Herrera would fare at Barca, especially as a La Liga winner like Arda has struggled to even make an impact.
Like I said, I dont doubt that Herrera retains his place. Fabinho-Herrera-Pogba will most likely be our starting 3 next season. But, out of those three, if we were looking to move up a level, who would be the one replaced? I would say Herrera, as (and you agree) someone like Verratti could come in, and instantly improve the lineup.