A lot of talk about which coins will be dominating in the future, however the current players are unlikely to be dismantled from their current positions any time soon: BTC, ETH, XRP, BCH, LTC. They may overtake each other at various stages, but their place in the top 5 is more or less cemented.
Looking forward, who do you think will take the lead at the #6 position this year? Currently it's Cardano, and they do have a solid project, team and fundamentals, so I don't believe they'll be easily eclipsed. However there are 3 serious contenders: NEO, EOS and IOTA - all Gen 3 blockchains as well.
What are your thoughts who will be #6 by EOY?
The assumption that the top 5 will be untouched is fairly bold. I wouldn't be surprised to see 1 or more drop out, most likely being XRP or BCH. Though they do have a long way to be caught in terms of market cap. NEO would be my pick to come closest to the top 5 but it does depend on how China decide to proceed with things, they can always throw a curveball.