I've got a 2015 model. The tap had a slight drip on first filling but this seemed to stop as soon as the water warmed. I think it was slight enough that the heat evaporated any moisture. I wouldn't bother replacing the tap unless it gets very bad though.
I wouldn't bother with a dip tube either as it is so easy to tip the unit to get the last bit out (just make sure you pull the BM to the edge of the table so you don't put pressure on the control unit)
Perhaps it's just me but I like to keep things original.
My buttons are fairly sensitive but get less so as you go from left to right. Again, not a major problem.