Some IATA airline codes are easily recognisable, while some are cryptic.

No one would hesitate to guess what AA, DL, KL, AF etc are. Who would have guessed what IT is, not to mention 9W, B6, WN. ICAO codes, as three letters makes it possible to assign recognisable codes to more airlines.

The same is for city codes also. Who would guess what YOW is, while ATL, PHL, DEL, AMS, HKG, BOM are recognised right away? The flexibility afforded by 4 letters makes it easier to assign recognisable codes to more cities than is possible with 3 letters. But I like three letter codes.
If airports have three letter codes, airline codes will have to be two letter codes other wise it would be impossible to tell whether a code is referring to an airport, or an airline.
So I am screwed. Do you prefer IATA codes or ICAO codes for airports? What about Airlines? Those who claim ICAO for airlines and IATA for airports will be sentenced to undetermined number of years to terminal confinement with TSA.

P.S. It tuirns out that Ottwa (YOW) and Toronto (YYZ) are just as cryptic in ICAO regime as IATA regime. Leave it to Canadians.