The wireless accessory charges through the micro-USB port on your tablet. Considering the fact that your port is already losing connection, it might completely break soon, and if the port completely breaks you won't even be able to charge the wireless accessory anymore which will make that purchase useless.
I suggest checking the cable to see if that's the problem first, because replacing a cable will cost less than replacing the whole tablet. However, if you know the cable is completely fine, then you should probably get a new tablet instead. Or you could fold a piece of paper and tape it to the cable so that it props it up in the position which disconnects least. That's what I did with my friend's Wacom Bamboo which was starting to disconnect a bunch.
The cable itself is about 10 months old, second cable replaced after getting the tablet, and I tried out a different micro USB cord, also used it on different electronics that take a micro USB cable and they didn't have any problems, tablet still had issues. I've also tried using the tactic of placing something under the cord, but it's not very affective since I have to have my arm over the cable in order to use my keyboard while drawing, I prefer using my space bar in Sai to move the drawing screen around.
It's a bit of a hastle to have the cable too, i end up misplacing it alot,so I was hoping the wireless accesorie would make things easier and more accesible.
Like I said, your micro-USB port is used to charge the wireless battery. If the port stops working (which it sounds like it will very soon), then you will no longer have a way to charge the wireless accessory making it a useless purchase in the end.
I suggest considering the newest Wacom Intuos 2018 with Bluetooth instead of another Wacom Bamboo which is just going to end up with another broken port.