Writing software to automate work is not the same as writing software to automate winning. You've eliminated the possibility of failure in a game where the possibility of failure is designed in. You've created an unfair advantage to allow yourself and anyone who uses that software to succeed where you might otherwise have a chance of failure. How is it different from aiming bots in FPS games? It's like saying, "I don't like aiming so I use an aiming bot" or "I'm not good at aiming so I use an aiming bot."
I, too, write software for a living. The software I've written keeps everyones credit card number encrypted so if they fall into the wrong hands they won't be usable. My software has automated the testing of electrical circuits in hearing aids so that people with hearing problems can hear better, and with a large amount of certainty that it will be nearly a perfect match to their hearing loss. The software I've written has automated grading of tests at colleges around the country. I guess I can't say that I've ever written software to automate winning at a game.
All solvers are more than likely a violation of rule 19 in the Dungeons and Dragons Online code of conduct.
19. You may not create, post or distribute any utilities, emulators or other third party software tools without the express written permission of Turbine.