I was thinking about drizzling chocolate ganache on a carrot cake with cream cheese
frosting. Do you think that combination will taste ok?

It will taste good. It will taste better if you put a pinch of cinnamon into the ganache.

If you have a choice, make the carrot cake without raisins or pineapple or cherries. Nuts and spices are OK. It's hard to say that something is good when each element is "over-the-top" by itself.

Taste is soooooo personal! What might taste good to one person might just taste awful to someone else. Just look at the posts about "The cake (or icing) is just to, to sweet!"

Personally, I'd love it. *ANYthing* with chocolate is good
It's not something I would go out of my way to make/eat but if offered I'd wolf it down.