My biggest concern is scalability, obviously, but there is other challenges as well. I was just wondering if anybody has been studying the subject before and can share her/his ideas with me?
Have you heard of the lightning network? My understanding is that atomic swaps would use that. So, it's highly scalable. You can buy litecoin 100 times over the span of a month using one bitcoin transaction and one litecoin transaction.
The way I have understood Lightning, it is focused on micropayments in its wierd approach: channels that work like buffers and are 'flushed' periodically while being managed by specialized nodes , ... (believe it? how some people are so excited about this proposal?) I don't think it can help cryptocurrency at all, specially it has nothing ,to do with chain to chain transactions, unless the two chains may be basically very similar (like ltc and btc) and they both implement lightning, and lightning has been developed for this use case, .... long, long time to go. I'm not so patient

Actually I'm talking about something to be done in a couple of months and even faster. It is agile era ... lightning is out of gas.