When it comes to monsters, it's true the "how many more hits can I take" question is something that you can't easily answer without a lot of internal math. To some extent, that's just the nature of games of this sort, especially when it comes to realtime. In most RPGs in particular, you can see a lot of the stats but the mental math about the number of hits that you can take really varies.
And for enemies it even changes when they change spells, so you really can't count on the numbers they show there. It would be better to at least show the percentage of your base health that enemy attacks will do, in addition to the raw number, in the pause menu. And we'd have to show that for all the possible attacks that they could do, which could be substantial. But that's probably worth doing at some point.
To some extent, I feel like we're getting overly analytical for the genre in terms of actual damage amounts -- how much damage does a given monster in Metroid do to you? You never know, but you can see exactly how much energy you have (as a number), as well as the other energy tanks. If you felt like cataloging exactly how much damage they do, you could. Even in Zelda, where it uses a really non-granular system of hearts to represent health and damage done, how much damage does a given monster deal to you? I certainly can't tell you, and I've been playing all the Zelda games many times over each since I was a kid.
The thing is, none of those things kill you instantly when you have a reasonable amount of health to start with. The general rule of thumb is always "don't get hit if you can avoid it," of course. But over time, you get hit some and can generally get a sense for what seems to do a lot of damage to you versus what does not. And so you get a sense for what to really avoid versus what is less of a threat. I think that the same holds true for AVWW, but here you have the added advantage of the numbers. If you know that Monster A is not that dangerous, and you can remember that it did around 5k damage, and you see that this new monster does 15k damage... well, this new one is a lot more dangerous. That can shorten the learning cycle in terms of getting a feel for the monster.
I don't mean to be overly resistant here, and in most cases I really like visual systems as well. But ultimately, no system that I can think of, visual or numbers-wise, would be any clearer than what we have right now in actual practice. People mostly need to get a sense for new monsters that they meet, and the vitality stones provide some security for that without so much threat of death.
I once made a suggestion on Mantis that we have ammo counts in the spell bar, like the health stones do. It would simply represent how many more times the spell could be cast with the current amount of mana. That could help with understanding how "big" your mana bar is without resorting to math.
I think that, for spellgems, that would be the best solution, actually -- rather than trying to adjust the mana bar. The only thing is, during actual combat it's really hard to ever look down at either thing, making them kind of low priority for me because I think the likelihood that anyone would ever use them is really low. And since mana is constantly recharging, these would be flipping around to an annoying degree. It might help with planning attacks, but even that is dubious because since the mana recharges while you are using spells, you'll always inevitably be able to cast far more than the count would hint at (and in many cases the real amount is "infinite, so long as you don't fast-click instantly when cooldowns expire").
That's why I'm a bit wary of making the interface more complex, or adding more numbers or whatever.
