* The maximum amount you can pay in a certain route is determined by the guy with the LEAST amount of money in his channel
* Users can defraud each other in a channel, so they have to continually check if somebody is defrauding them.
* Unless you have a direct channel to your target, there is NO guarantee AT ALL that you can pay the person you want to pay.
* Users need to be online 24/7 if they want to be part of a payment route. If a user is offline, this particular route is not possible which of course has huge impact on the possible routes.
* Insane amounts of data are being sent because the network needs to be aware of EVERYBODY's payment channel's state (otherwise it can't discover a route)
* You still have huge fees if you want to wire money into/outside the channel.
* It's not feasible at all for bigger payments. Let's say you have to pay $1500 rent/month, are you going to open a payment channel and deposit 3 years rent in it ? Most people have difficulties enough coughing up the next month. But if you have to wire every payment into the channel, then you could just as well pay on-chain because you're paying that exact same on-chain fee.
* It's also not feasible for very small payments/channels. If you open a $30 channel with your coffeeshop to buy a few cups of coffee per week, then the price of your coffee doubles because of the huge fees to open/close the channel.
* Who is going to lock up his money in several channels anyway ? Liquidity, needed for routing money, is going to be a problem
* Very difficult to use and explain to users. No way your mother let alone grandmother is going to understand all this.
1 - True, but LN is meant (in my opinion) for small transactions anyway, so this is less of a problem than you're claiming it to be. Also, at a certain adoption level there will be multiple payment routes.
2 - Correct, but why is this such an issue? Is this a manual thing you have to do all the time?
3 - Correct, but there are no guarantees in many things. If you care about all your intended payments being possible in the early stages you will make sure you are connected via multiple channels which will reduce this risk.
4 - I think a lot of people will run nodes 24/7 to earn fees and they will become (mini) hubs. I know hubs are bad for decentralization, but not if there are many of them.
5 - Not sure on how the amount of data would compare to for instance the data stream for huge blocks so we can all buy beer (why does it always have to be coffee?) with our BTC
6 - They don't have to be huge if LN is used and that reduces the load on the blockchain. I also think the blocks will eventually be increased, just not to the gigabyte blocks bcash is talking about, but to whatever is needed and doesn't lead to centralization (8mb? 32mb? who knows?)
7 - LN is not meant for these amounts in my opinion, but still you don't have to have a channel with everyone you interact with. Payment providers could solve this.
8 - You don't have to do it directly with the coffee shop, lowest level users will end up having a channel with a payment provider who will have a channel or routes to the shop.
9 - I have several bank accounts, I see no problem here. Why do you see the funds as 'locked up'? They are in a channel so they can be used. Do you consider your money at the bank as 'locked up'?
10 - I doubt your mother or grandmother know how a phone signal works or maybe even how a car engine works. Doesn't mean they can't call or drive.