It's not magical skills that I am talking about. Literally the planets and the cosmos have to align for this one particular ability of East Indiamen (and to a lesser extent Carracks, but that wasn't the focus of the conversation) to be useful. And this is in the context of underrated UUs, so that means this scenario, which I describe as uncommon at best and more likely rare, has to occur often enough that I will wish I had the Dutch UU to exploit the opportunity. I'm not convinced.
I'm not saying every game. I'm not saying every few games. I'm saying that I can only recall a handful of positions like this in my entire Civ4-playing career.
And frankly, random events like all your melee units getting Cover for free are about as rare in my eyes but also helpful as well. If I described a new civilization's UU as a "once every so many games, you might get this extra ability, maybe"...I would probably be laughed at.
You missed the point. Which is, even without this particular ability they are almost on par with the unit that obsoletes it and because of it sometimes better. Cover event is a bad analogy, a better one would be a good-in-their-own-right Axeman UU that in rare circumstances can be better than regular Macemen. That's an indicator of power IMO, no matter how rare the situation (which isn't actually that rare on water maps which some players favor a lot). Galleon as a base unit for one's UU still sucks of course compared to Axemen or such.
For the record, I don't think EIs are generally underrated - if something the opposite, people tend to overrate water UUs even (or especially) for water maps IMO ("There's water, so a water UU must be good!"). That doesn't say anything about their real power level of course which kinda makes this whole discussion off topic.