The GT 740m can generally play many, but not all games with decent performance at 1366x768 resolution and medium quality settings. Click the following link to check out some game benchmark results.
http/www.notebookcheck.net/NVIDIA-GeForce-GT-740M.89900.0.html
If playing games is your primary concern, then I recommend dropping down to a dual core CPU to afford a more powerful dedicated graphics core which will give you better game performance.
Heat depends on the specific laptop, but laptops do generally run hot when playing games.There are two things you can do.
1. Buy a cooling pad preferably one that blow air up into the vents on the underside of the laptop. Most inexpensive cool pads do not blow up, instead they blow down trying to drag excess heat from the laptop. This is a less effective cooling method.
2. Disable Turbo Boost. This will definitely lower heat, but it also lowers performance.Therefore it may not be a "preferred" option for many gamers. This can be done in the Advanced Power Options in the Maximum CPU Performance section. For Windows 7 it was easy, just set to 99%. In Windows 8 it is different; you need to determine the actual (or close enough) % between the standard clockspeed and Turbo Boost clockspeed.
For example, my current laptop has a Core i5-4200u CPU with standard clockspeed of 1.6GHz and Turbo Boost clockspeed of 2.6GHz. To disable Turbo Boost I have to set the Max CPU performance to about 62% (1.6GHz / 2.6GHz) if it set it to something like 68% or higher Turbo Boost is still active.
CPU temps when playing games:
Turbo Boost On: 75C
Turbo Boost Off: 64C
The temps of the i7-4700MQ will likely be higher because it has 4 cores instead of 2 cores. The i7 is also not a ULV (ultra low voltage) CPU.