Just so you know, the main ledger does use address comments.
You mean the main transaction list you get when you first start the client? I know it does, and, because of how useful it is, I find it hard to work without it. Memorizing a bunch of BTC addresses is a lot harder than reading English that you wrote earlier.
I can look at adding it to the tx viewer, as well. Though, that table is already cramped enough. I guess you'd ideally be able to customize which columns you want.
That would be the best, most 'flushed out' applications allow you to simply right click the columns and add/remove them, also drag them around, etc..., but, it could be as simple as a check box in the settings.