Personally no, your current Macbook is more than capable for the next 4-5 years. Don't get caught in "the latest tech game" because there is always something around the corner. As long as "your software" is supported by the hardware you have no reason to.
CPU wise looking at maybe a 10% increase in speed. The obvious factor is power consumption in which you get an at best 1-2 more hours (not as big as the Air with a staggering 12 hours).
GPU wise it's the same as the CPU all the 750m is, is just a rebranding of last years 650m (no joke look at the specs the 750m is just a re-clocked 650m). The extra 1GB of VRAM won't make that huge of a difference since games will still struggle to be playable at higher resolution.
Flash storage wise yeah they added a 1TB one but for 500 dollars more (so your paying a buck for each GB). Yes the added speed is nice but so far that speed hasn't been noticeable (I have a 2013 Air with the updated flash).
TB2 yeah it's great but do you even have any TB devices? Then again is there even an affordable TB device in the market?
In the end your looking at minor upgrades, if you really must get an upgrade I would wait for update to the display (IGZO).