I think it may be useful to allow the addition of a comment to bump a question.
Please no, that is a bad idea.
I have multiple reasons why I do not like the idea at all.
First and foremost, I don't like comments very much. I regard comments as obsolete by default, especially when they are old. All relevant information should be contained in the question or the answer itself. Editing things mentioned in comments into the question will of course change the status.
Second, there is already quite a lot movement on the active page during certain times of day. Comments are quickly and easily created and they would only enhance this mumbo jumbo more. If every comment will bump a question, then I would suspect an influx of even more noise comments.
In the worst case, real contributions, like answering and/or editing a question will get completely lost in all the noise.
There are oh so many comments, that say just "thanks", or "great answer", etc. that simply do not add any value to the question itself. I don't want a 30 (or more) day old question becoming active again, just because the OP only logs in once a month. (Accepting an answer does not change its status.)
Third, there is already an official way to make a question active again. Give it a bounty. If you can't add any more/ better information to the question itself, and you want it to be seen again, then advertise it.
Fourth, the status of a question really does not say anything about the question itself, it's basically a book-keeping tool, but nothing more.
Feature requests like this would affect the whole network. Therefore they should rather be asked/suggested on mother meta.se.
I feel that since the comments are literally just commentary and aren't meant to answer a question that this would just bump up old questions that don't need to see the light of day again.
Comments I often see or write:
- "Thank you so much! That works."
- Jokes to lighten the mood (that relate to the question or an answer.)
- Complete disagreement.
- Suggestion for improvement in answer.
- Further request for help. "If that is the case, then how do I do this?"
While not all of these are pointless, there's no real need to bump up a question for any of the above comment types.
Nobody cares about a thank you. Jokes are great, but again, not important. If a disagreement in the comments bumps something to the top, we're inviting more people to come play in the crapstorm of discontent which is bad for morale.
Any suggestions for improvement or requests for help in the form of a comment are sent to the OP or answerer as a notification so they can address it.
The comments are a great area for minor chitchat without having to conform to the rules of you asking a suitable question and me giving a suitable answer. It's more free, if you will.
If you bump up questions with comments, I feel comments are more likely to be negatively viewed by the community and will become annoying and frowned upon.