I don't run ps2 or wii emulator. But iirc, these emulators are not multi-threads optimised (please correct me if I am wrong  ).
If the above is correct, then you don't need i7 quad core, just anything Intel with as high single core clock as possible.
The SLI in Y500 will be totally wasted since these emulators will not be able to take advantage of SLI.

i) of course the Y500 run hotter when in SLI
ii) You do see big nice gaming laptop with good built-in cooling system normally come in 17" right? Yes, size does matter. Internal component layout is important. Thermal paste, fan / heat sink used in laptop. .... 15" is definitely better than 14" for heat dissipation.

If you manage to get your laptop die due to overheating, you must have done something terribly wrong  
Good external cooling solution (a cheap table fan go a long way), good air flow, periodic maintenance cleaning of laptop fan / air inlet/outlet from dust, re-applying (good) thermal paste ... some of things you could do to prevent the pain

Yup, clock for clock, Haswell is more power efficient compared to Ivy Bridge.
But currently there are not much Haswell spec laptop in Malaysia yet. Have to wait a bit
For your purpose, a Sandy Bridge i5 will have no problem running those emulators

You mean this one?
GE40-2OC, i7-4702MQ + Nvidia GTX760M + (1600x900; anti-glare)@RM3999[1.8kg], 8GB, 750GB(7200rpm), W8

thermal profile is not good 
Is there any specific reason you want 14"? Portability?
For that price, you could get:
www.illegear.com
Illegear RE-15, i7-4700MQ + Nvidia GTX765M + (1920x1080;matte)@RM3599[Onkyo], 4GB, 500GB(5400rpm), FreeDOS [CPU Options: i7-4700MQ - i7-4900MQ]

But to run the emulators, I would rather do something like
Lenovo
Ideapad G580, i5-3210M + Nvidia GT630M@RM1699, 2GB, 500GB, freeDOS, 1 yr warranty
Then put in a 512G SSD, as much RAM as I want, still < RM3k  

iirc, ps2 emulator takes a LOT of CPU power. GPU - yeah, GT630M maybe is a bit weak    (I was just trying to make a point on wasting money on i7, hope you don't mind )
unfortunately in Malaysia, laptops are generally not very customisable.
To run ps2 emulator, I think your ideal laptop will have:
i5 M CPU with highest clock speed. If ivy bridge, that will be i5-3380M which turbo up to 3.6GHz. But laptop in Malaysia normally come with i5-3210M (3.1GHz) or 3230M (3.2GHz).
The RAM, I think 8GB should be fine.
The storage, 256G SSD could be have for RM600+/-.
Then just spend the rest of budget to get the best GPU possible. Just don't waste money on SLI, cause ps2 emulator could not take advantage of it.

Good luck