I think that sports betting gives you the most odds to win because if you know the teams and how they play and what quality are they, you van easily win. It is also the easiest kind of gambling to find a loophole in, if you know someone that knows the results ahead on the rigged game. Other games such as dice or other depend on a random generator and does not offer you much odds on winnings.
Blackjack is probably on number 2 because you need to know to play and you control part of the game. You could also count cards if you know how to.
1. sports betting never gives you the highest odds atleast on pre-live betting because sports betting sites are made like that. they never give you high odds for the selected team that is most capable to win.
2. i believe that dice offers much better odds than sports betting. btw, @op, winning in a dice game is not so easy because higher the odds, lesser is the chance to win.