Some flavors stay with the atty for a long time so blowing them out or even dedicating an atty and cart to certain flavors is done by many - the ones that I have "dedicated" are licorice, coffee, and menthol. Others tend to blend well so a complete cleaning is not needed, at least for me, between some flavors.
As for the chocolate, hes, there are some that seem a bit more chocolaty as opposed to a... hmmm... earthy feel. I have started routinely adding a few drops of sweetener and vanilla (Tahiti Vanilla now thank to some little mouse on the forums) to every chocolate I use - really brings out the flavor. I tend to find most chocolates just have a dry, earthy taste (not bad just not what I want.
Good luck on you explorations - that is half (most?) of the fun! Welcome!