This would make the summoner spell 
more off a situational item.
a nerf would be for example more Cooldown.
On the other side "Stormraider´s Surge" is going to be viable, and provide mages with mobility in combat.
I really think ghost is an important summoner spell in the game, but in his current state, he is just to strong taking away space for other summoner spells
oh, ghost is taking away space for other spells? it's too strong?
ghost, you say?
Ghost is already a situational summoner spell except on a select few champions. It's for chasing and running away, but still not as good as flash since it can't avoid cc as well. Barrier protects you well if you have a bad early game or are in a tough matchup, teleport is good for snowballing and getting back to lane. Heal is for an ADC and ignite helps you get an early lead.
Ghost doesn't really need buffs, it's there if you need it (melee champions). Buff it and then ranged champions can prioritize it, breaking them. They're slow for a reason.
Stormraider's surge is already really strong on champions like Veigar or Cassiopeia. Mages aren't supposed to be mobile, so buffing it is going to break them.
No because not all champions who use would use Stormraider's. Ghost is only really good on a select champions like 
are the ones that Ghost is very important on. Obviously there are other champions that can work well with it as well like 
but none of these besides for would really use Stormraiders. So this idea would just nerf their synergy with Ghost.
Though I have seen Ghost getting picked up a lot as a secondary summoner spell now thanks to Worlds but even then, I don't think it should be nerfed because of it.
