There are two major lightning node implementations. So the pool of talents is now split. There are less eyes on wither project than there could be. There are competing agendas. And it's an extremely complex protocol where bugs from incompatibites are constantly arising, to the detriment of the users' experiences.
Discussion
I'd rather that than everyone trying to fight for consensus in a single codebase, even though that's the most "efficient" way to do it. But I don't think efficiency helps a decentralized system grow strong, however frustrating that is.
And even if there were only one lightning implementation, you still need people to update their nodes to expand the protocol. But people tend to update blindly. If there were a more diverse ecosystem, one update in one implementation wouldn't put the whole system at risk.