User blog comment:LivesByProxy/Summoner Spells Redux/@comment-24420226-20151228043209

The reason why Flash is so dominant is that it is so versatile and, despite it's large cooldown, it can make a big impact in a wide vareity of situations. You can use it as part of an initiation, dodge big damage/CC ablities, escape a gank or other bad situation, chase down kills, etc. The fact is that the live versions of the other spells are designed to have a narrower range of uses which makes it harder to justify their use over Flash. This is the core of mobility creep and why simply trying to buff numbers to compensate for low-mobility doesn't address why mobility has such a premium - mobility is a flexible tool that can give an advantage in multiple scenarios, where more damage/bigger shields/bigger heals are ony useful in a limited number of stuations.

If you are serious about dethroning Flash, you need to try and make the spells useful in more situations. Think about how adding a breif movement speed buff to Heal instantly made it the top-tier summoner spell for bot lane - that small kick of speed could be used for more than just surviving a fight longer. Some of the changes you have here are going in the right direction (true sight on clarity and invisibilty on ghost). But others are not - namely splitting Exhaust into two seperate spells. This further drives both of the components into niche uses. Since they both have the same duration, Stifle is the better spell since it can still reduce incoming damage from any type of carry, but Exhaust is only effective against marksman or attack-speed fighters and is virtually useless against burst-oriented champions (which one should expect to have in any teamcomp).