This is not a list of what changes to perform, nor does it include stat changes, as I am not knowledgeable enough to suggest those; these are just some modifications I thought would make him more interesting if some were to be implemented. Each ability has some suggestions; I would like to see how you would want the champion changed or adjusted, rather than simply increasing damage, resistances, or other stats.
Passive:
Reduce HP granted from 15 to 5 (necessary, otherwise he becomes too strong with the suggested changes).
Also restores mana, using the same percentage as the health.
Increases health restoration, perhaps scaling from 4% to 8%.
Can pull again from teammate crowd control.
Deals max HP damage on pull.
Q:
I think that for this, either the pierce would have to be removed or the "pierce only on kill" mechanic would need to be reintroduced.
Deals max HP damage if at least 3 bolts hit.
Pulls a shard when at least 3 bolts hit.
Fires more bolts based on stacks (or more damage per bolt)
Executes based on stacks (not the biggest fan of this due to too many executes are in the game)
1 second CD in ult form
W:
Massive damage increase, i am talkimg like xerath q and similar hard to hit abilities.
Like Wild rift, crits on cc'ed targets for more damage
More damage based on how far away the W is
Marks target for increased damage for some time or lowers mr
Lower explode time im Ult form
E:
Like anivia q, can be recast to turn back at any point.
Explodes when hitting a champion
Ignores minions, pets etc
When returning explodes around swain
Larger hitbox or speed in ult form
R:
Remove permanent ult, it is so low elo skewed it cripples his change potential.
Massive increase in healing and damage, works just like aatrox ult (base duration plus increase per kill or per stack ammount, whatever is best)
Demonflare pulls shards from hit enemies but has longer cooldown, or marks enemies so that the next demonflare pulls shards.
Each demonflare does more damage, like 20% or sth
Gives hp on cast and doubles stack health. Health gained on cast could also be based on stacks with a base ammount (like 100/200/300 + 50% of stack health)
Ult area size increases with stacks
Which one would be your favourite change combinations? You can also pick more than one per ability.