Of course it matters, he is basically gegging in on Ranieri's managerial skills. People are forgetting Leicester were almost relegated till they swapped Pearson for Ranieri, but all of a sudden Walsh was the mastermind!
Loons.
I think you (and they) are being incredibly simplistic. Raineri did not win anything (in England) before Leicester, yes? So he can't win with just any old group of players. Walsh brought in these players (mostly under Pearson). Pearson was crap and they were nearly relegated. But it clearly wasn't the players Walsh bought! Raineri won the league with them!
So perhaps success is not entirely dependent on a single individual, but more upon a number of individuals working as a team? Thus Leicester's success is down to - Raineri, Walsh, their physio team, steroids, the players themselves, a bunch of terrible seasons by the traditional powerhouses, and a whole bunch of people I have no idea about?
Walsh did his job well - buying players with which Leicester could succeed. Whether he is singlehandedly responsible for their league win is both a red herring, and insane.