First, his criticism had nothing to do with our spell names. It had to do him thinking that the original DQI&II translation by RPGOne was nearly perfect as is, extremely important to gaming history, and that my group would commit some kind of great sin by tarnishing it with a new translation. I gave him multiple examples of significant translation problems in the RPGOne script.
Second, did you play through one of our projects? Or did you read a list of spell names and get annoyed? Two very different experiences. I've had a couple people read the list and criticize our work, but I don't think we've had a person play through a game with them and not offer specifically positive feedback on the naming scheme. I'm not saying criticism in that context isn't possible, but it seems rare at best. You make this odd comparison to someone driving on the wrong side of the road and causing a crash, but... I really don't think our spell names are that confusing. The meanings are mostly obvious, especially if you start with DQ1.
I did think long and hard about which direction we wanted to go with this. I get the different points of view out there, and I definitely get not pleasing everyone. If it was like Final Fantasy where the English versions (Fira/Firaga/etc) are pretty close to the Japanese versions, we probably would have just left the existing system in place regardless of where it diverges. But in DQ's case, neither English system works or feels anything like the Japanese system. And a translation is a translation. Our approach was not one of fan service, but of faithfulness to Horii, however that gets received by English speakers. Spells, like equipment, like character names, were all treated as part of the translation in the end. There are definitely people who appreciate this approach, as many have expressed.