Fourfold weaknesses

A general opinion among Pokemon lovers is that Pokemon with double weaknesses are generally inferior. This isn't true at all. Aggron for example, is amazing with very high  base defense and a versatile movepool. Weavile has a double weakness to fighting but it has extremely high speed and equally good attack along with being able to learn ice punch and night slash. Aficionados should simply not pit these Pokemon against foes which can defeat it, like a Weavile shouldn't be battling a Machoke or something. This is true for all Pokemon with even single weaknesses. Just don't use the Pokemon against the strong dudes! Catch others which can overcome the latter's weaknesses. Players may think they know this but they complain that their Pokemon are useless. Teach them moves that they can use against them; like teach Weavile aerial ace. However, it is better to catch Pokemon which are fast so that they can escape these attacks. Torterra for example is used against water types but many of the water types can learn ice moves, which doubly damages Torterra(grass/ground). Also Torterra is quite slow so a move like Blizzard takes it out from a faster Pokemon like Floatzel.