I really want to complete my National Dex but I missed a lot of the events so I was just wondering.
>In Pokémon Black and White, Professor Cedric Juniper upgrades the player's Pokédex to the National mode when the player first leaves his/her own house after defeating N and Ghetsis. As with previous generations, event Pokémon including Keldeo, Meloetta and Genesect are not needed to complete the National Pokédex.
Source: Bulbapedia
If you mean the full 649, yes, you need events. Definitely. I believe it's impossible to complete a national dex without hacks, as there are some Pokemon that haven't been released for events. Such as Shaymin. Genesect. Meloetta. So, sorry...
