So Lightwell gets a 40% healing buff, and a cd reduction.
It feels like blizzard have no clue how to make this spell work.
I actually tried it, to see how bad it was, and the spell has many problems.
First of all, it gives a hot to players below 50% it cannot cast on multiple players simultaneously (only 1 players pr. second). This means that you can’t use it to counter raidwide damage, as it simply spreads it’s healing too slow.
You cannot move it either, and it’s range is only 20 yards. Meaning unless the raid stacks on the lightwell, you get close to no value.
The core problem isn’t the healing throughput when the healing occurs (well, thst is also a problem, but that is just number tuning). The problem is that is often times doesn’t heal at all. The conditions for this spell to perform good are insane is it is.
A hot to a dying target is terrible. And raid members shouldn’t rly get lower than 50% anyway, except for big raidwide damage, where the lightwell doesn’t work either. It feels like it dosn’t even have a niche right now.
My suggestions for making lightwell playable is one of these 3.
1: Increase it’s range to 50 yards.
This would just make it a not completely unusable version of what it is now, since it might actually hit something without depending on the raid stacking on it. If they do this, increase the size of it, just because, huge holy well 
2: Let it heal multiple targets at once
This would give it a niche in prolonged raid wide damage situations. And let it get some healing out for soaks mechanics and such.
3: Make the cooldown shorter, like 30 seconds, but let the lightwell last 3 minutes still. Let the priest have as many lightwells up as the cd allows.
My personal favorite. Having small lightwells scattered around the boss room. Placing them proactively on important spots where the raid is gonna stack. Would be nice.
Last but not least the healing should also be waaay higher. Not sure if the 40% buff is enough.
Hoe do my fellow holy priests think this talent could be fixed?