Indeed, we need to up the technology of bitcoin first before we find something to replace it otherwise it would repeat the things where bitcoin failed at. Besides, there are many coins that are at par with bitcoin right now, only difference is their application--like eth and xrp. To be creating a new "bitcoin" is very counter-productive.
Well, the only thing that bitcoin is not good at for me is their fee's when it comes in value I have nothing to say about it but when you combined the value and the fee's it can destroy your belief. Once bitcoin increase the fee also increases. I think we should just work on the problem of bitcoin and stop chasing what is better than bitcoin. If fee's problem solved for sure it will leave a big impact on the bitcoin industry that can lead to its successful again.