With those criteria there are no players. Because none has ever been able to bench likes of Pique and Busi for 3-4 games in a row.
Pjanic is one example though, that I'm certain of is worse than Busi.
Azpi could be a good backup, but we don't need backups.
You need some criterias. Can't compare players who are starters for years with those who are here for just as season or two and never got a fair chance because captains just have to play based on their past merits.
You can be certain he would be worse than Busi but we'll never know for sure because Pjanic never got more than 2 consecutive starts.
Anyway, I'd prefer to see what new players can bring and risk them possibly not being good enough than have to watch the same players doing the same things (which we mostly know are not good enough) for the millionth time.
And I've also said I wouldn't expect Azpi to be a starter (unless he'd deserve that) but I'm sure he would bring more to the team than Busi or Roberto these days.