Barry had been an England regular for around 2 years before he came here.Darren Fletcher and Park Ji-Sung were crucial for the Rags in Europe; no English team is ever going to dominate Europe with a tiki-taka style of play.
An English team in Europe has to be dynamic, decisive and defensively synchronised; you can't out-pass Barcelona, so why bother trying? Our quickest route to the pinnacle of the European game is the Atletico/Dortmund way; with dynamism and a team of compatible players who all maximise and neutralise each other's strengths/weaknesses. In that regard, Delph can do the graft that Toure and Silva can't, allowing them to focus on making an impact in the attacking phase. The role Gareth Barry used to play, and one we haven't been able to properly fill since.
The signing Barry in 2009 wouldn't have excited too many either, but he proved to be a fantastic buy; the parallels between the two players are there to be observed. Barry had just established himself as an England regular, as Delph has. Both were Villa captain at the time of purchase and both have a similar simplistic passing game that keeps play ticking over. Only difference (beyond race) is that Delph is a bit more tenacious.
We've tried bringing the likes of Garcia and Fernando in, highly regarded midfield anchors from abroad, and they've both been unable to cope with the physicality of this league. Delph ticks every box and will hopefully provide a long-term solution to that problem.
They both have links to Aston Villa, I'll give you that similarity...