The biggest issue I see with the lightning network is that it will have the opposite effect that the devs are thinking it will have.

If the LN network is successful, the number of transactions will go up, not down.  Its designed to do micro transactions etc at a lower fee.  This will bring in more users which will need to buy coins on LN/open channels.  Both of these result in more transactions hitting the btc blockchain.  Doing the math, even with bigger blocks, (guessing 24 tx/s) this allows 64 million channels to be open or closed a month.  Now 25% of that space is already full, so its really only 48 million, or 24 million open and close actions.

So the LN networks own success will be its downfall.  If it gets popular and poeple switch to it, it will quickly fill up the btc blockchain with people depositing/withdrawing coins from it.  The average person gets paid twice a month, so they will likely be depositing twice a month.  Thats only room for 12 million people to open and close channels.  This isn't even accounting for merchants wanting to cash out daily/weekly at most. 

The problem is that the LN network was designed for three things and the developers forgot to account for what happens if its successful.  It was designed to improve transaction speed and lower fees, while removing transactions from the blockchain.  The issue is if its successful more users then ever will be using the blockchain.

Just my two cents.