I´m absolutely excited! 
I especially like that most of those changes will assure players at a long-time hiatus to faster catch up with the pace the game evolves, enabling them being competitive sooner again.
Devs, please let me have my time and find attached my own thoughts and suggestions for future considerations as follows:
Boss Battles
I´m happy my former albeit a bit different suggestion for a game mode using a unique, defined deck for AI controlled opponent did hit the spot. Great decision to try something completely new. There are many options for a nice boss battle challenge, I´m very happy to see ´em coming! 
##Boss Crates
I embrace the idea. 5 USD per player is a fair charge for your work in comparison for the contents therein. Also keeping you motivated to serve us new game contents in the future to keep Duelyst fresh.
##Free Card of The Day instead of Daily Challenge
A bit pity, but a fair decision as for players on a hiatus to catch up faster (or for new f2p players to quicker build up a competetive card collection). Personally I´d love to see this game mode again.
##Monthly Cards, bigger Expansions and Seasonal Special Events
Rarity creep is a thing. You simply can´t increase the percentage of Core-Orb rarities without skewing the game in a totally different direction when there are too many of epic or legendary cards.
Bigger Expansions are just bigger expansions. We will see what you have in store for us. This implies, please be careful as you will have to rotate out expansions after some time to still being able to reduce or enhance card strengths for those special culprits.
Seasonal Special Events sound interesting. If able, please elaborate further. Nonetheless, great that you let the standard Season Reward Crate untouched.
##Match History Maintenance Note
As I´m a relatively new player, I don´t care too much. However, if you´re in touch with the guy who´s creating those widely and highly accepted helper tools for Duelyst, please consider to build-in those codes natively into your application. So one can chose which one to use, checkboxing within the options.
##Sneak Peak: Continuous Draft Mode
This looks especially exciting! I´m wondering what´s it all about and am happy to learn more upon further disclosure. If the card drafting will be based upon own card collection, this would be somewhat more exciting and a great more meaningful alternative to simply just grind the ladder. We will see.
The only bad feeling is about some too crazy power horses due to wild cross-faction card combinations. You however will know what you do.
##2017 Roadmap
Great and thanks for the hints!
##Free Keys
Personally I´m not interested to care for a youtube or a twitter channel. But it´s a great token of gratitude towards many of those players who otherwise won´t (or can´t, for some reasons) pay for your service.
But when we´re talking about keys, please consider to reduce the average costs for all keys. It just doesn´t feel feasibile to invest mainly into cosmetics for these price layers.
That´s all for now, thanks for reading! 
