If I search MIA-KUL, it shows me AA7441 via CDG and AA7436/AA7343 via LHR.

MIA-DOH gives me AA7994 via BCN, AA7970 via IAD, AA7974 via ORD etc etc.

If you look for a flight by itself (LHR-DOH), it does not show the AA codeshare as AA does not market this flight unless it's a connecting itinerary. AA7436 LHR-KUL or AA6589 LHR-PRG appear because the codeshare can be sold as a connection AND as part of a stopover.

It is surely best that we only see the codeshares on connecting itineraries? If I search LHR-HAM, I don't really want to trawl the dozens of codeshares.