Potentially limiting mining to those with tens of thousands of dollars to spend in a pessimistic scenario. Going further, what if the ASIC producers refuse to sell? Self mining while protecting their ASIC designs in the courts.
There won't be only one ASIC designer. Don't worry about it. ASICs will drive the price of LTC much higher. The reason is simple: the initial few ASIC adopters will be very profitable since there rigs are faster, thus driving the price of ASICs high. As more people use ASICs, mining will become much less profitable. Miniers will then consider choosing between the following:
a) spending 2000 dollars to buy ASICs to mine just 2 LTCs in 3 moths
b) spending 2000 dollars to buy 4 LTCs
LTC price thus goes much higher. This is what we've seen in BTCs history.
By losing some miners, you will see more buyers of LTC. There need to be just enough miners in order to secure the network, not too many of them. But a successful currency needs more investors. LTC initially need to be GPU/ASIC proof in order to have enough miners to prove it is secure. But now I think there are more than enoughh miners.
I'd rather not see a couple of data center type mining farms being the only ones hashing for litecoin.
If this would be a problem then BTC would encounter it first. LTC will then still have enough time to avoid it. Being a follower takes much less risk.