If I were the thread starter, I would prefer it posted in the thread than PMed, that would hopefully eliminate repetitiveness.
Personally I don't find thread drift that bothersome, esp on this board. Because it is an etiquette board most people are polite when they reply, even when they disagree, additionally i think the group we have here is rather intelligent, articulate and logical. It would be one thing to reply with "You're stupid, I don't think any woman should change her name because it's a bad idea" But that is not what we get here.
On this board we are more likely to get someone responding with tactful honesty, can a logical argument. To me it is different to say " I personally don't like name change and here is why. . . reason x, y & z". To me as long as logical reasons are stated, and the post is polite and non-judgmental, I view the post as welcome, since you never know when a reason will resonate with the op, or someone else facing a similar problem. Now we should strive to not turn it into a debate or a lecture but information, opinions, and reasoning to me are always welcome.
I don't actually think "don't change your name" is an unreasonable response, since it does solve the problem. Yes it is a third option, but sometime third options are very good and very appreciated. I am always open to food for thought, you never know when you will hear something from a different angle that really clicks for you.