I LOVE writing crossovers, but I have a set of very specific goals when I do one.
First, it HAS to make sense as a story on its own. I do not want loyal readers not getting a great issue just because of a crossover.
Second, I want to take advantage of what the mega story offers. I like the tapestry of the DC and Marvel universes and crossovers allow you to play with that.
The Secret Six came from a crossover. The Court of Owls was a crossover. Crossovers are great fun, when done right.
But when it’s just marketing, you have to work EXTRA hard to make sure they are worth reading.