Many new cryptocurrency projects copy already created technologies and therefore such projects have no future at all and it is not worth investing in such projects, also the creators of new projects simply abandon their projects for various reasons, and of course, most projects list their cryptocurrencies at scam exchanges where the price of any token will drop to zero.
I think to have an easy job in determining if a project is legit or not, we should only look at where it's listed, once it's listed in a non reputable exchanges, then you should doubt their future, but when listed in a popular and reputable exchange, you should believe that they have a chance to grow in the market as exchanges themselves are not stupid to list a scam projects.
Another aspect to consider is the legitimacy of the idea. Most ideas are just recycled and called with a new name but we cannot blame the Cryptocurrency Industry since most bounties before were just made to create profit and that is a cycle within this Industry. Only few platforms are considering to further develop their system because sometimes they are losing supporters midway and that is bad since they want their platforms to be used on the daily.