>>38330306Anon, being 16x effective against one thing isn't necessarily better than being x4 against that same thing when it introduces drawbacks that prevent it from being superior.
For example, people run Ice Shard to take care of Garchomp, Landorus, Salamence, Rayquaza, and other things with a x4 Ice weakness. Say that an Ice/Water Ice Shard was introduced. Using it over the new one would let you kill Landorus a lot better, at the cost of losing any effectivity against Dragon types (except for Garchomp who keeps the x4).
People often run Ice Beam/Thunderbolt because it gives you near-perfect coverage, but folding those moves into one doesn't give you a superior move because now you'll never be able to hit Ground types. Same for Stone Edge/Earthquake and Flying types.
