O hai, I'm Riot Sparkle and I'm going to write a long answer because I never get to talk shop about stuff like this and I'm really excited. :D
So maybe make that panel more useful and put cooldowns and other things there where applicable.
So, this suggestion is a pretty dang good one - I know because it was actually originally how we had the in game rune panel set up tbh. We had different rune cooldowns and changing damage values on there, and the idea was to provide tactical "in the moment" information on the in game panel.
However, in practice (i.e in testing) this didn't work out so well. Players needed the information on the buff bar for many of their existing abilities and buffs, and attention was divided between the two spaces. This meant that players often missed important rune info because they were looking at that teamfight action - and the rune panel is farther from the action than the buff bar. Hence, we decided to move keystone cooldowns etc. to the buff bar instead and group all of that "need to know now" info together.
Additionally, we found that players were actually most often using the runes panel in a "moment of rest", while dead or in the base, for example. And, generally, having a cooldown or value of "0" for something wasn't very useful to them in that use case. Stats like you mention for the quest runes, for example, were far more useful.
Now, this isn't to say I think we've perfected the formula of showing information on the runes panel - we still have an upcoming task to do a giant sweep of both in-game and end of game rune stats to make sure we're showing the most useful things we can and to push the two rune info spaces further apart (players tend to want different stats during the game than after it from an evaluation standpoint). So, basically, I think there's more work to be done around rune stats for sure.
I've also talked about how we're going to be evaluating individual runes more often now (ex: Manaflow Band) to see if they need to display more tactical information on the buff bar to be used effectively. The danger there is indeed in overloading that space, which is why we're pretty carefully weighing each rune that goes up there, but I think that runes like Manaflow or Null Orb, despite being normal runes instead of keystones, certainly earn that spot.
**TL;DR **We are concerned about having too many things on the buff bar BUT at the same time it made sense to group all of the tactical information you need together in one spot visually, or else it was actually really hard to use that information when you needed it. Also we have more work to do in the runes stat space.