Introduce a direct Harrow to Ealing bus route,
linking at least town centre with town centre.
Takes under 20 mins by car; but a very awkward
journey by bus/tube, taking up to an hour, with
multiple changes.

Why not interchange from the 182 to the 83 at Wembley Central?

Because it's an extremely unreliable route. The 182 and 83 are both
prone to delays and bunching; 20-30 mins total waiting for buses
occurs far too often.

It's not even the quickest way with theoretical average waiting times.
Try sticking Harrow-on-the-Hill to Ealing Broadway into the TfL
Journey Planner: it doesn't come up with that route, or indeed any
route with less than 2 changes.