If we (magically, i have no faith in this) get Weigl for example, I'd expect us to have a top midfield for around 6-7 years before needing someone to go in for Herrera. I believe having a already settled midfield for those extra years means getting the extra bit out of them.Yours was one of the posts I was responding to, but you're not alone. The thing is, how long can you realistically expect a midfield to stick together. You could easily get 4 seasons out of Matic. That's plenty of time. And whoever we get, I wouldn't be surprised to see us targeting a midfielder next year anyway.
(like Xavi & Iniesta partnership at barca for example, where they for one were top players, but had played together all their lives so performed even better as partners)
I'd be surprised if we would get Weigl & then target a new midfielder the next summer, at least if it's not for backup/rotational purpose.