I started a project with arduino pro-micro because of it's built-in USB support. Now that I am adding components, I have to do a lot of code/component tweaks just coz I am using pro micro and not mini etc. I have already sweat a lot on this. I am wondering if it is time to move on to a new board. If pro-micro is at the end it's life, I would rather learn some new board or go back to the good old pro-mini
There is no such thing as Arduino Pro Micro. Arduino has never made one of those boards as far as I know. You would have to check with the manufacturer about whether or not they intend to keep making them. Sparkfun designed it and makes it, and many manufacturers in China copy and sell it. I kind of doubt they are near end of life. The design is based on the Leonardo, it is just smaller. DF Robot Beetle is even smaller yet.
I'd advise avoiding the ATmega32U4 based boards such as Pro Micro unless you specifically need their unique capabilities(such as Keyboard and Mouse library functions). Otherwise, I'd recommend you to use ATmega328P, etc. based boards instead. If you only want the onboard USB for uploading and serial communication then use the Arduino Nano instead.
There’s nothing wrong with using '32U4 chips in your design. I offered a Leonardino (little Leonardo) for a while, Pololu.com offers a '32U4 board that is similar, you will always be able to find some version of a 32U4 board, or design (have designed) your own with your other components so you can control your own destiny.
If you don’t need USB support, and only use it for serial print debugging & code downloading, then go with a 328P design and just plug on an FTDI Basic or equivalent for USB connectivity when needed. Most everything I design goes into embedded products, so I just put on a header for an FTDI Basic for development. If I think it might need full time USB, I provide a spot to add a USB/Serial module like MIKROE483 that I buy from Mouser.com, you can see one here:
Cross Roads Electronics
The Arduino "Pro Mini" is a sparkfun ATmega328p based board with no USB support.
The "Arduino Micro" is an Adafruit/Arduio collaboration with an ATmega32u4 and "native" USB support.
Both of them are little more than breakout boards for their respective chips, so there isn't a lot of "design risk" in using them in a project. Also, there are a lot of other 32u4 based boards from other vendors. So I don't think there is any particular reason to avoid the 32u4.
OTOH, something like a Teensy3 might be a better choice - a more "modern" cpu environment.
And the Pololu 32U4 version:
A really small one
And a larger one
available in blue, green, white it looks like with different regulator supplies: