Yes, we've added this in 3.20.

We've discussed community feedback around this, specifically to consider options around instance-pausing, colour indicators or reward symbols. Each of these options has their own drawbacks so we won't be making any changes on this front for now. The best thing to do is to finish killing the surrounding monsters before reading the Altar.

When you kill the Maven herself, the chance of getting an Awakened Gem is quite common. The drop chance from Maven-witnessed map bosses is a lot lower than this because these fights occur more often. The goal is that they're common enough that it feels worthwhile running Maven-witnessed maps while not having Awakened Gems feel too common and significantly lowering their value.

The exact weighting hasn't been finalised yet but currently, we're looking at them being slightly less common than Rogue's Markers. Note that that is on top of other sources of Scarabs like Altars, Delirium, Betrayal, etc. (As we mentioned, these drop less frequently from Altars in 3.20, but other sources haven't changed).

This change only applies to rewards from Influenced Monsters. Altar rewards that say things like "Map Boss Drops Three Vaal Orbs" will still drop in stacks of three requiring one click for pickup.

One of the goals of the Altar changes from the outset was to retain the feel of Altars such that the gameplay feels familiar, as we're generally happy with how that feels to play. Part of retaining this means we want to keep the frequency of encountering Eldritch Altars relatively common. If we want to give you Altars relatively often, it means we're giving out rewards relatively often so one of the ways of balancing this is to make the stack sizes of those rewards lower.

Most Currency rewards from Influenced Monsters already dropped in stacks of one, but there were a few outliers (most notably Map Currency rewards). The outliers are generally the only thing that is changing here in terms of stack size.

We have no plans regarding this.