I completely agree, we need a rework on most summoner spells.
Ghost needs a rework as it's only really situational, and only useful on specific champions. This is not my idea, but I propose Ghost leaves a trail behind you that speeds up allies, or maybe even slows enemies as well?
I just came up with a crazy idea just now, what if a summoner spell had a passive buff?
For instance, what Inept Maverick said:
Barrier should give bonus armor and magic resist or percentage reduced damage.
Not sure if he wants this on the active or not, but if it is, I don't quite like the idea of it being an active. Barrier is essentially used for when you're about to die, to survive a little longer to either kill or get away, it feels wasted if you're just only trying to get away, only just to give you an edge of health to survive, I can see it being useful in an escape situations. Maybe I'm wrong, and it could be used offensively.
Here's where the passive buff comes in, what if instead, it were a passive buff? Maybe it could give 5 or 10 Armor/MR, or perhaps percent damage reduction like Maverick proposed, but I much rather like the Armor/MR, as it seems more balanced, so it would be there in all situations. Just an idea.
I also hate the fight between Heal and Barrier, it seems one is always going to be better than the other, and ADC's usually rely on one these two alone. If only there was some difference that would stimulate decision making between the two. I have no idea's on this, at the moment. Even with the Barrier buff I proposed, I can still only see it being useful in solo lanes if anything.
All-in-all, summoner spells really need to be reworked, at least the underpowered or underused ones.