@Blackmamba
I agree that it will be a major challenge to cope with the additional capacity in terms of keeping quality at the current level. When it comes to demand on the other hand it would almost be a crime not to expand that fast. Let's go through your arguments:

- Singapore Airlines example
This is one of the best examples demonstrating why Emirates should expand. Singapore Airlines lost customers due to high fares (bad cost structure) and NOT because of a lack of service. Suggesting anything else is the same as claiming that Ryanair is loved for its excellent service and hated for the high fares. Over and above Emirates expansion will reduce costs on a lerm term basis (economies of scale) and therefore helps them avoiding a bad cost structure (the reason for Singapore Airlines subtantial drop in profits).

- @ crew members
Of course crew members will all turn mad and Emirates surely can't effort new buildings (but they can pay 90 A380's...). And of course capacity for new buildings is very limited in Dubai - a city in the middle of the desert.

- advice: hub and spoke
Hub and spoke won't work for Emirates with the exception of flights to Australia for obvious reasons: HYD-DXB-MIA (hypothetical) is no big deal but HYD-DXB-IAD-HYD with a connection at one of the miserable airports in the US (very few exceptions) is simply no alternative.
And suggesting to codeshare with US airlines doesn't make sense when you are warning of declining service standards: Most non-American people would never board the aircraft of an American airline if there is a way to prevent it (even if JetBlue and Virgin America are admittedly comparable to European airlines - but NEVER on the level of the ME3). In fact there are many cosmopolitan Americans thinking and doing the same.

- Las Vegas "Sin City"
Are you serious about that? We are talking about an airline of the UAE, a liberal Arab country with a modern Islam (even for Saudi Arabian Airlines I doubt that this argument would make sense). Over and above Thailand attracts about a 1000x more sex tourists than Nevada, consequently they would have to stop serving Bangkok.

- expansion of Philippine Airlines
Very simple: If an airline is superiour in terms of service, price, network, ... then there IS room to expand. PA and also most airline in Europe/North America are poorly managed by a bunch of dinosaurs, therefore airlines in these regions are unpopular among world travellers and additional capacity is not appreciated/required by the market.

@Omar84
Until they can't see an opportunity to make more money by expanding capacity will continue to grow.