Itoje was very good against Wasps yesterday- he offers a proper lineout option and was a real neusance at the rucks (big hits too- dislodged the ball a couple of times). I'm not sure where Sarries will use him once Kruis, Vunipola and Brown are back- he may be a bit short for a lock, but he needs to be carefull not to get too big and immobile for a no.6, having said that, some improved ball carrying work in the tight and he could be exactly what England need in the no.6 role to partner Robshaw/Vunipola (which is a bit of a poisoned chalice imo), since out of all the current options he combines lineout option, with big ball carrier and and being a bulldozer at rucks.
As I've said before, bringing in the likes of Ewers/Kvesic will only slightly improve a fundamentally flawed back row, because it will still be deficient in at least one aspect of play.
Ewers + Robshaw + Vunipola = wrecking machine, but also sloooow, no specialist jackal threat and a shaky lineout.
Kvesic + Robshaw + Vunipola = faster and jackal threat, but again no lineout option of note.
Funnily enough an in form Wood (the bulkier version) was probably the most balanced yet (still not optimal) with good lineout, decent ruck work, but only average carrying.
Haskell is decent, but lineout is still poor and he is a bit bulky/slow without exceptional ball carrying to compensate for this.
As above, Itoje could turn out to be a good hybrid (maybe not yet though).
Robshaw + Vunipola = problem. (cue the hissy fits)