Lets see what they have in common to get a feeling at which areas Karma shines and where she does not.
Long range pokes, decent farming, in built-sustain, zoning to a certain extend; shield
Karma can poke with
but not as safe as Morgana can. Her sustain comes from
(though E is not very reliable, see skill order). She can zone most enemies thanks to all her spells.
Morgana can zone with
but if she misses her
, the pressure falls off. Karma can clear entire waves with
, Morgana must use her
and can miss alot of CS this way (even if its safer).
only absorbs magical damage, but prevents her from being CCed. Since Karma should max
2nd, you get a lot more absorb from it, possibly negate all the damage you receive in the duration of most CCs.
Both have their pros and cons, but considering Karmas Skillset, I guess she has a point here.
Morgana relies on hitting with a single-target line skillshot which can be blocked by minions, Karmas damage cannot be blocked because every spell is an area effect.
Her shield is weaker in most cases. Her root is extraordinary good but easily dodged. She has no sustain so it is harder for her to go solo top. The burst is comparable, but Lux has more range on most of her spells.
If Lux misses her
, she is no threat to most enemies anymore. Karma can slow enemies with
most of the time as long as she remains CDR capped. This allows for her complete team to chase (and even escape) and slow the enemy in the same time.
Karma can kite a lot more than most champions can due to this fact but she needs quick hands to perform this.
Karmas shield is stronger but doesn't give a small amount of armor and MR. W can be better in certain situations and worse in others.
To escape and chase over a longer period,
is stronger, but
is less dangerous if you can land it in between your enemies and your team.
Another downside of
: you must maintain the beam while still being in range. That means you need to be in a dangerous position sometimes.
Karma can deal more area damage over a longer time but needs to take a greater risk doing so. Orianna can't heal and has no real sustain whatsoever.
Except her ultimate and some more range (not so high since recent nerf), Orianna is not better in any point,
is just situative as well as
is. Both, again, have different pros and cons but no spell is plain "better".
Karma excels against melees (except
) and enemies with predictable (single) damage sources and damage-over-time-spells. She hardcounters especially:
(unless fed) and some others. She is also effective against
to a certain extent.
Shielding targeted abilities with travel time (
) or Skillshots that cannot be dodged for whatever reason but have a certain delay (
Karma renders champion like
useless, since she can slow him 90% of the time and shielding his
+some seconds of
in the same shield.