I'll bite.
1) There is a problem here at all. The regulation that is being repealed was only introduced 2 years ago; how did we get along before that?
Yes, there is a problem here. ISPs have already started overstepping the bounds by extorting money from Netflix. T-mobile has a plan out right now that gives you unlimited Netflix, but rate limits everything else. This is a violation of the principles of Net Neutrality.
Yes, there is a problem.
There wasn't much of one before, because the ISPs were very careful not to upset the balance. In the past five years though, they've started seeing what they can get away with. Net Neutrality regulation is a response to the ISPs testing the waters.
2) This problem can be solved by this regulation (not all regulation achieves its goals, and sometimes it is even counter productive).
Probably. It's fairly easy to say "all ISPs have to treat all packets the same." Then have yearly audits of internal routing infrastructure.
3) Regulation is the best/only solution for this problem (what other solutions to the problem described in 1 have been proposed, and why are they not suitable)
I don't believe regulation IS the best solution. Not so much because the regulation itself is bad, but because each set of people who get into power have a different idea of what the regulations should look like, so it ping-pongs back and forth ad-infinitum.
I think the best solution is for towns to build municipal fiber that competes with existing ISPs. The infrastructure could be rented out to local ISPs who compete on the publicly-owned lines. If Comcast wants to charge people out the ass for shitty service that rate limits (or hell, censors) certain websites, go for it...but there are 20 other local companies who give faster speeds for cheaper prices that support Net Neutrality.
The problem is, Comcast generally stops this kind of market competition from happening via propaganda campaigns and jamming through state laws that prohibit it. A municipality entering the market is still a free-market competition, so it should be an option supported by libertarians.