Movement speed what it does exaclty unless I'm missing something

Ok let me make a break down the things movement speed do for us :

**1. Mobility. ** Moving faster allow you to waste less time out of the fight and use more time in the fight. Assuming you have no mana, cdr and sustain problem this could improve your total damage proportionally.

For example if you buy a pair of boot which increase your speed by 7% and you spend 25% of your time returning to your lane. it will be reduced to 23.3% after the boots. Effectively making you damage from 75% of your time to 76.7% of your. An increase of 2% of your damage.

2. Range traversing If your champion range is smaller then your opponent range you spend less time receiving damage without dealing some yourself if you are faster.

The math are the same as the mobility chapter just above. Let's assume a melee champion lose 33% of his hp bar before he reach the adc (which seem the upper acceptable limit). A tier 2 boots which increase his speed by 10% would. This would decrease the amount of time traveling and increase by 5% the amount of time dealing dmg.

2.1. Hit and run The same kind of effect could be used to mitigate damage when you have very long cool down skills. You can enter the enemy range, drop your damage and get out of it. It would be very unlikely that this strategy would allow you to slowly 100-0% your opponent without him taking measures. The figures are much likely similar to the melee champion who would have to close in the enemy except for different reasons...

**3. Range control ** If your champion have a preferable range and is faster then the opponent he can stay in that range. this would be theoretically infinitely good if we were not stopping to auto-attack and if there were no towers or teamates to stop the chase at some point. Actualy it's not a bad buff. I'd estimate at around 15%.

The problem is that it's a one time buff which only occur when your speed beat the opponent. In this game with all those speed buff, gap closer, slow and flash. The speed vary widely from 1 player to another. You'd be lucky if a pair of boots would make you faster then 2 opponents.

4. Skill dodging Yes ! but no. Running faster increase just as much your odds to run into a skill shot then it does to avoid one. This is only true when a visible skill shot can be dodged after the start. and only if it can't be dodged easily already. And still only when you are willing to dodge in the relevant direction (personnaly I aim my skill shot to be dodgeable by moving into even more troubles and much as I can).

The only thing that come to mind is Nidalee spears when mid range. It's unlikely that more then 25% of your damage will come from that kind of skill shot. And it's generous. Those damage can be mitigated by ms.

** When I add up everything... ** I conclude that if you are a melee champion, a champion with high cooldown or if the movement speed makes your faster then your laner and if there is some skill shot to move out. 1% in ms bonus should roughly scale you by 1% (give or take).

Now am I missing something crucial ? I'd be glad to review my copy if anything else is missing. Because for 365gp I can buy boots which would increase my speed by 7%. But I could as well reduce my physical dmg by ~12% with a cloth at 300gp. Or roughtly increase my hp by 12% with a ruby for 400gp when bought early. which are 2 other good option right ?

Am asking because I personaly feel they are gold efficient, but not enough to start a flame war with someone who would feel it's better to spend on something else...

I'm gonna mention one last thing I suspect that tilt the balance for a lot of players ** 5. Fun ! ** Woohoo I'm so fast around a tower with that raptor cloth ! WeeeeeeeeEEE. GG I won the game. (that's what i feel every time I have a raptor cloth). Doesnt make me win more or less, but I get why people could think it's a must. The only reason why I could explain why everyon want boots. OR they expect that 15% buff to be constant maybe ?