First of all: sorry about my paint skills
What you mean exactly by "too much information per entry"? If you're talking about the altnames textarea, this was asked by community. I'll see if we can make it as popup (dialog).
The "Subject alternative names is too much. This column takes about 8-10 text lines. In combination with the blue header bubble I see in full hd 3 rows. It would be better if you have a edit button and if you press it this information pops up. (Like PhpSettings on domain creation.) The new place could be filled e.g. with next renew date and/or issued date.
Well, can you clarify here your idea about alt link. I'm not sure to understand.
I thought it that way (and yes I know it is ugly):
(This leads to a better overview. And I think it is not necessary that the complete url needs to be visible always. A link would be enought. In my picture it would be "[alt url]" - please find a better name