A short complaint on summoner spells
Summoners, as they exist right now, feel rather lazy to me. For the most part, they're some sort of flat boost or debuff.
I just pure flat, damage,
is just pure, flat movespeed, and
is just pure, flat health. These are all, by their very nature, rather simple to use, and does not require much thought at all. Just ask yourself if you need some more dmg, some more movespeed, or some more health, respectively. On the reverse, they feel really shitty to play against, becaue there's little to no counterplay. How do you outplay a person just popping a huge shield on you, or just getting a free 210 true damage from a single, targeted spell? You can't, and often it just becomes a matter of 'you can't win cus I have a massive stat advantage over you', which feels shitty.
and
are currently the two most well-designed summoners in the game, because they both require intelligence to use properly. Just flashing close to somebody won't do you much good in a fight, unless all you need is an auto-attack or two. Generally speaking, making use of flash requires great understanding and good gameplay. You need to dodge something, or you need to use it for a massive engage, or some other big play, which is what summoners should be used for: BIg, impressive, smart plays.
Teleport exists on a similiar spectrum. Teleport won't help you win a fight, it requires forethought to actually use properly. In lane, you need to understand how wave-management works properly to use it, you need to understand map-pressure, splitpushing, and so many other factors, which is what makes it so skill intensive.
In conclusion, Riot should try and innovate more with summoner spells, make them more exciting. There is so much room to explore there, beyond just pure stats.