The text I quoted is from page 69 of the Rules Compendium. The only sentence on that page containing the word "immortals" is the one I quoted, and it seems pretty clear that it is stating that immortals can understand any language, and not that everyone understand them when they speak Supernal. That ability seems pretty clearly limited to gods and angels.
I'd be fascinated to know how they're going to determine the bolded bit, and why you believe this is the "new plan". Is there a L&L to that effect or something?
As for "a better game", well, I think that depends how much you like house rules. Personally, my experience with them is very mixed. I sometimes like my own. I almost never like other people's. I suspect most people are similar.My favourite games have required few/no house rules, though, and I doubt that's coincidence.
My concern goes the other way - by the wording of the DMG, devas don't have any sort of universal language, but by the RC wording they get univeral input (but not output).
Not a clue. That bit really does seem to have been sneaked into the Rules Compendium out of nowhere. I can't find any other 4e source indicating that immortals (who speak Supernal) automatically understanding all languages.
As far as I can tell, it is only immortals who know Supernal that get that ability. And devas don't automatically start with Supernal, they start with "Common and a choice of two others". I probably wouldn't let Supernal be one of those other two languages unless there was a really compelling story reason.
It makes sense for gods and angels to have a univeral receiver to go with their universal transmitter (at least, that makes sense to me - and I had interpreted the DMG remarks about a "universal language" to imply as much). It's the generalisation to immortals, hence devas, that I don't get. And have not applied in my own game.
It's from Dragon Magazine 374:
