Ok, let´s relate your answar to the question..
"Why Is MEX Such A Difficult Airport To Operate?"
Ok, Mountains should be a problem on the approach.. or at difficult days, where you have terrible WX conditions.
Language differences?? What the .... really I can´t find something related to Aviation... (I.E. I should ask LH498 pilots, if they have problems when they tune MEX_TWR while they are on the VOR/DME2 Approach (ex. Mateo 6 Arrival) if they have problems with language when they request landing clearance in English.)
Should rwys be clanead every.. month?? every 3, 6. 9 months?? I can imagine airports like KLAX, KLAS, KMIA, KJFK, KORD, etc, always with very HIGH TRAFFIC DEMAND, and when you check on the ATIS (Airport Terminal Information Service) Active runways... I can imagine hearing "Rwy 04R is closed by cleaning manteinance, be aware of all cars, traffic, cleaning the runways".
About the wet taxiways, and runways.. there´s nothing much to say.. that REALLY is BIG problem, on months which rain a lot in the City.... but we have to remember that Mexico City is above Texcoco lake... so that´s why we have big flood problems everywhere.
Not a pilot for now... but I can said there are factors to consider like WX Conditions (Temperature, Dew Point,Humid) and the airport altitude (7,343 ASL.)