At this stage it's mostly speculation. I don't think anyone can truly know whether Segwit (and by extension, Lightning) is good or bad for Bitcoin until we see it in action. There are still concerns over maintaining direct access to the blockchain by individuals, so users can keep transacting directly on-chain without relying on third parties. For those who believe the advent of this technology could result in users being forced off the chain onto more "custodial" services, then it's fair to see why they're skeptical. To echo others, this clearly doesn't make it an altcoin, but it is potentially a significant change in ethos. On the plus side, it is optional and, if it doesn't work as advertised, there is still the nuclear option of a hard fork away from it.
I do not believe it is all speculation from the people who are against Segwit/LN. It is also political because they have a different set of beliefs on how Bitcoin should be taken forward and has divided the community into their own camps. The people in each camp who point at each other accusing that greed and control is the primary motivation of the solution of either Segwit/LN and bigger blocks are hypocrites. Both camps each have their own self interests at hand.
For what it's worth, I'm interested to see Segwit and Lightning up and running so that we can all make an informed evaluation of the pros and cons.
I agree. I am also interested what else can be done with LN. The most interesting use case is the possibility for it to become a bridge to other blockchains.
However, I will say that (despite usage being optional) if people feel they are either being forced to transact either less frequently, or off chain, due to prohibitive costs, or if the off chain transactions start redirecting fees away from the miners and towards some newly created middlemen, causing incentives to become misaligned, then a fork would be all but inevitable in my view. People won't support a system that doesn't support them. Give it a chance, but not carte blanche.
True but it will not stop the miners from creating payment hubs. I see it as an opportunity for them to gain more power in the system.