Why is it I see so many people go pure builds, like everything AD or AP or AS? It makes more sense to me to use a variety of items; AD + AS + Armor + LS, for example. It could be just the characters I use, but this pure building seems to ruin the combat dynamic a little bit for me. Fights aren't fights, they're slaughter, and that seems a bit silly considering these are supposed to be "Champions" or "Legends".

IMHO, building a variety of items should be encouraged.

How long have you been playing?

no one builds pure builds if they get boots its not a pure build anymore because it gives speed

Building pure AS or crit is retarded as those dramatically increase the value of AD. Whether or not building pure AD/AP is viable depends on how the hero's skills scale and whether they can mitigate or avoid damage naturally.

AS and crit also have hard caps at 2.5 and 100%

how about riven, talon, and pantheon?

they will get items that give primarily AD because they are casters

just like casters get primarily AP items with drings/roa + dcap because they work solely off that one stat.

Fights in this game already last a long time compared to the other games in this genre, so if you think they're quick fights now you'd be in for a surprise if you ever play HoN or DotA.

Champion builds are the way they are because, generally, they're the most optimized version of what that champion needs. If they need a lot of AD, then they're going to build a lot of AD. If their one skill that scales with AP is pointless to get AP on, you won't see them build any AP at all unless that AP is a byproduct of picking up some other item. Purposefully building sub-optimal item choices for the sake of "dragging fights out" is just not a good idea in a competitive game. Maybe if you only ever played by yourself against bots you could get away with this, but you're in a game with 9 other people, and all of these people want to win the game. To win, they're going to try to build only the good items their champion needs to perform.

It just seems silly to go pure damage, when a single armor piece significantly improves survivability, without compromising much offensive power.

Cuz they want to go PKing in the wildy duh