Scalability problems is the main problem that bitcoin will face if the community will decide to accept segwit. I am not against segwit but there are just some things that segwit needs to settle before they can start with bitcoin and that I say is the problem on scalability. Bitcoin unlimited on the other hand is nice but there are many errors and bugs and so it is much safer to stick with segwit as long as they can find a way to settle the problem on scalability.
Xester, thank you but it sounds to me that you are saying everything you mentioned has a problem?
The proven option with least problems and the solution to the world's money/store of value problem is and has always been bitcoin.