League-of-legends – A question about Attack Damage red and Armor Pen Red, which is better

Rammus' powerball appears to be a % speed increase, reportedly increasing about 10% of his movement speed per second.

This means a Rammus with 5 phantom dancers will have a significantly faster powerball than a Rammus with just boots.

http://leagueoflegends.wikia.com/wiki/Movement_speed

The reason Rammus appears to avoid the soft caps on movement speed is because Powerball compounds his movement speed - it's being reduced by the caps, but it's still a significant enough amount that it does increase, which means the next application of Powerball's "speedup" tick will apply more than the previous, even with the soft cap.

These can combine to push Rammus' speed into egregious territories.

Generally speaking? No, probably not.

Mostly because AP characters value levels over items in most cases, and in bot lane you'd be having a support sucking up XP. Overall, this would mean that the enemy's AP carry in mid is becoming stronger than the AP character in bottom lane, while the allied AD carry in mid isn't becoming notably stronger than the enemy AD carry at bot. AD carries scale with items, and not really with levels. Thus, the AD carry wouldn't really gain anything from being in mid lane.

The majority of AD carries also couldn't lane against the majority of AP carries. While AD carries would start off strong, with decent pokes, once the AP carry gets to level 6 and has a Doran's Ring or two it is pretty much game over unless they've fed. There is no way an AD carry can keep up with the raw control and damage of an AP mid. Regardless of who the mid is.

The only exceptions to the above rule would be Corki, Ezreal, and possibly Urgot. Corki actually does scale with levels, as does Ezreal to an extent. Urgot is just innately tanky with super long ranged harass. ALL of those characters would have mana issues though, and would have to rush a mana regen item to compensate for that. And Corki and Ezreal would still have trouble with high burst/high CC champions such as Cassio/Annie/Ahri/Karthus/Just About Every Popular AP Mid Right Now.

Specifically speaking? Sure!

There will always be specific situations where you could counter certain champion picks by using more elaborate strategies. This is where a lot of the original "meta breaking" strategies come from. Such as running kill lanes in bot, double AP carries, double AD carries, or even double jungle. It can work in certain situations, but it won't work on a regular basis. And will rarely if ever work in solo or duo ques.