Irelia is really not that strong herself, she's so popular only because right now ranged is insanely strong compared to melee and Irelia is the strongest melee when it comes to dealing with ranged toplaners and diving and stunlocking ADCs, due to her reseting gapcloser and 2 seconds stun (other mentions in dealing with range are Fiora, who doesn't have utility and is thus extremely feast or famine, Jax, who got nerfed too hard, Renekton, who scales too bad for the current hyperscaling meta, Maokai and Akali, who are as FotM as Irelia if not more).
As long as Ryze, Jayce and Gnar dominate toplane, Irelia needs to be there to guarantee toplane doesn't become ranged only. Ranged toplaners, though, cannot be nerfed too hard as long as ADCs stay so strong. If toplaners get nerfed and ADCs don't, toplane will become COMPLETELY irrelevant, even in TP plays, and Riot knows this, hence the promise to bring Ryze's power back after a gameplay update, no nerfs for Jayce yet, buffs to Akali's early game (with not so great nerfs to her late), pretty much irrelevant nerfs to Gnar on PBE.
I think this is the current situation.