It would be nice to hope MS would learn and make sure all the bugs were worked out before they released a product, but no... I expect the same or perhaps new bugs, but what I meant was you should spend your money to get significant hardware upgrades and as @hughlle said other than a larger screen there's no much difference in the SP3 and SP4. I'm hoping a SP5 will be a big jump up from the 3.What are you hoping to be different with the SP5? Wouldn't you expect it to have the same issues?
You can have the virtual keyboard auto-pop up in desktop mode by going to Settings -> Devices -> Typing and toggling on the bottom option "Show the touch keyboard...."
If you have never cleanly installed Win10 on this machine (ie. only upgraded it from Win 8.1), I would recommend doing the USB approach.