Blind, I can see yeah.
Though, it really gets me wondering sometimes. People are so, well, lonewolf in these games. Like, I'll see five people on one team with ignite (yes, I've seen this). I've seen an adc take barrier/ignite while his/er support take heal/exhaust.
It just gets me thinking that people don't realize that "selfish" summoner spells are less powerful than teamwork orientated ones. Say a team with ignite and a team with exhaust get into a teamfight at full health. The team with ignite can "tickle" their enemy with ignite for .1-.25 of their max health total (whether they use it for the kill, be dumb and use it at the beginning, or use it to limit healing is disregarded for this situation), while the team with exhaust can basically half the enemy's burst damage, lower their defenses and movement speed, and lower all sustained damage to a 1/3.
With this in mind, I say that exhaust... might be better than ignite.
But there's other spells. I see top laners use teleport to get into lane to farm (for the first time, yeah, but after that it gets...) but NEVER use it to join teamfights or help another lane, then blame the team when they never get kills or lose.
Heal is better than barrier in bot lane because it heals almost as much, heals two champions instead of one, the shield is temporary but the health stays if you're not hit, and gives a speed burst useful for that little extra range for a last hit kill.
Blah blah blah, team-orientated spells might be better than "selfish" spells designed for a single champion to benefit from.