On Malazan: As LSU stated, he explains much more as you get through the books. That 1st book might as well be the Prologue for the series but everything makes much more sense (for the most part) as more is revealed. There are still people and beings in the books that you will always wonder about and where they come from, but the magic system and much of the backstory of the characters from the first book are revealed later on.
Other recommendations outside of the Epic Fantasies we all kepe talking about (WoT, GoT, Malazan, Sanderson, etc):
"American Gods" by Neil Gaiman; few people have mentioned this but this is a great take on a modern day myth/fairy-tale about about the cultural melting pot that is America and what happens to Gods here.
The Night Angel series by Brent Weeks: What is not to like about cheering for the boy turned assassin? Great action packed story.
The Gentleman Bastard series by Scott Lynch: Imagine someone took Ocean's 11 and dropped it into a fantasy world. The writing is perfectly paced, amusing, and the cons are great to read. Plus Scott Lynch seems to love describing and inventing food, which has inspired sites to create actual recipes from his descriptions.
All of the Jim Butcher books, just all of them. I prefer Dresden Files over Alera Codex but both are good. Dresden has some great humor in it. Imagine Harry Potter turned 30, decides to be a "magician for hire," moves to Chicago, and is now a wise chull. It's kind of perfect. Plus Bob.
"Jonathan Strange & Mr. Norrell" by Susanna Clarke: Personally I thought this book was great. Historical fantasy set in England and one of the wars against France, about two magicians in an otherwise non-magical world.
The Iron Druid Chronicles by Kevin Hearne: 6 books about a druid in modern day America. It's a very engaging read, and shorter than most of the stuff I recommended above.
"Promise of Blood" by Brian McClellan: Revolution era (guns!) like setting with an intriguing magic system. This is the start of the Powder Mage series and if the second book is as good as this one, he has a long career.
"Blood Song" by Anthony Ryan: This is another great first book, which if the follow-up is just as good will be very interesting. Follows the legends of the main character moving through his life and this is the first chapter (he grows up quick, it doesn't keep him as a teenager long).
Traveler's Gate Trilogy by Will Wight: This is the debut trilogy by a self-publishing author, that so far I have found to be very engaging. They are relatively quick reads with an intriguing magic system, amusing characters, and a very engaging writing style (IMO)