The Arduino Wire library does all that.
No it doesn't get over the problem:-
the arduino will have to run in slave mode. This means it can't initiate any communications by itself, it has to wait to be polled by the Pi before it can send data back.
Yes there are ways for it to run in slave mode using the Wire library, but that does not mean it is a good idea.
GPIO pins 14 and 15 on the Pi, are serial lines, you can connect this to the arduino's TX & RX. The only thing you have to watch is that the arduino sends a 5V signal so put a 330R between the arduino's TX and the Pi's RX line with a 3V3 zener diode from the Pi's RX line to ground to bled off the extra voltage.