Answer 1

The creators wanted to make a change and make it harder to obtain good Pokemon. Previous pseudo-legendaries like Dragonite, Tyranitar and Salamence typically have very high evolution levels of level 50+ for the final stage. But in B/W they made it even more difficult.

For the Deino line it's level 50 to get Zweilous and level 64 to get Hydreigon. Some of the later Unova Pokemon like Mienshao and Volcarona also have high level evolutions.

Answer 2

Deino is one of the ending pokemon for the main quest in pokemon Black and White. He comes as a lvl 36 or higher so you only have about 10 more levels to go. He isnt that hard to train. For me I just go threw Victory Road a bunch of times. I sometimes go to the Dream yard to train him. I already completed the main quest, get reshiram or zekrom and defeat Ghetis and Team Plasma. Im just training my Deino to complete the pokedex. I need 7 more. One of them is Zwelious.

Comments

One of the things that confuses me, is that there seem to be pokemon, namely the pan or simi trio that either need more experience, or don't earn as much experience as others. I've had no trouble leveling my pokemon up without an issue, but Deino, and Panpour seem to earn less experience than most. Maybe I'm wrong, but even with EXP. Share, setting them first, and switching them out so they get 3/4 EXP instead of half, or even using Lucky Egg to boost EXP gain, they seem to gain less experience than the rest.

Answer 3

Deino evolves at level 50 wich is very late for a 3 stage evolution.

Comments

How is this incorrect?

---

this doesnt answer the question

---

It does kinda, to evolve at level 50 is very late, and if he didn't already know that that could be the answer.
however pokemasters answer was more detailed.