Can you see either of them easily fitting into the current starting XI not just regarding form but ability (as a first choice anyway) ?
I was thinking the same about O'Brien, never really been a fan of the diamond formation as it can allow the opponents to dominate the midfield but it seems to be working quite well for us, not sure where you would slot O'Brien in to that.
Yes The lads currently in the team have made the most of their opportunity. When the likes of O'Brien, Perkins, Mido, Done, Steele, McNulty, Silva, Digby, Stones, etc. are presented with their opportunity (and they will be), I see no reason why they can't also make a positive contribution.
Mido would bring a little guile and skill upfront, so a different threat to Dagnall but a good option to have.
Re: Yes Dagnall doesn't play a 90 minute game. No disrespect to him, his contribution has been massive but it happens over an intense hour. Can't see Jim fitting into the current favoured diamond, but he's an option against teams who stop us bossing midfield and playing through the middle. Also, knowing our luck with injuries, they will all get their chance at some point this season.
The other players currently out of the team Will bring different strengths to the table to those being replaced for whatever reason. It also means the midfield diamond being utilised at the moment may not always be the formation Keith Hill opts for.
Re: The other players currently out of the team I think O'Brien could play on the right side of the diamond. Works hard. But as others say, we may wish to play a straight 4-4-2 against some teams, or 4-5-1.