Diego's more like Adam than Modric, and that trio of midield would be horrific defensively, Gerrard and Adam or Diego would be too offensive.
Besides we have too many attacking and creative midifielders already, unless we plan on selling one of Gerrard, Meireles, spearing, aquilani, I don't see us getting an attacking midfielder, maybe a defensive midfielder to back lucas.
For DM duties you have Lucas then have either Gerrard/ Merieles or Adam/Diego as CM Hazard RightW, Young LW that behind Carroll and Suarez will be heart attack inducing for most defences.
Aquaman will be sold and can see Shelvey going out on loan for a season, as Kenny will want him to get some more experience as Shelvey is his new Gerrard.